In “On the Use of GM Screens” a few years back I shared my personal best practices when it comes to using GM screens. Probably the biggest reason I like them is the vertical reference space: One of my secret weapons as a GM is simply arranging my reference material so that I can lay out multiple elements (stat blocks, room descriptions, campaign status document, maps, NPC roleplaying templates, etc.) simultaneously. I can thus cross-reference material by just flicking my eyes back and forth, and can often easily compare information directly instead of having to flip back-and-forth.

The vertical reference space of the GM screen, therefore, is basically free space. I’ve already covered every inch of table space in front of me (and often have a TV tray to one side for additional reference material), so basically creating more space in the third dimension is a huge advantage.

Now, the most common thing I put in that vertical space is my system cheat sheet. It’s virtually always useful when running a game, and putting that information into the vertical plane means that my horizontal surfaces can be focused on scenario-related material. These cheat sheets can also be prepped ahead of time

But this is not the only way you can utilize that vertical space! This is a trick that I didn’t think to include in “On the Use of GM Screens” because I don’t use it very often, but it can be very effective upon occasion and you may find it even more useful than I do.

Basically, 3M makes these removable restickable glue sticks:

They can be used to essentially turn any piece of paper into a Post-It note. And that, in turn, means that you can turn any piece of paper into a swap note that you can quickly paste up or remove from your GM screen.

For example, you can print out the stat blocks for your current scenario. Here I’ve grabbed an Orc War Chief accompanied by a warband of Orcs, and also a second encounter featuring a Werebear and his pet Owlbear:

And then, while running the game, you can quickly use the restickable glue stick to attach them to the GM screen for easy reference during an encounter:

Other stuff that you might find useful as a swap note:

• A list of upcoming, timed events for the current session that you don’t want to forget
• The map of the dungeon
• NPCs in the current scene
• The standard features (door types, ceiling height, light sources, environmental effects) of the current dungeon
• The daily weather forecast for the next several days of a sandbox campaign (so that you don’t forget to make it rain)

As I’ve talked about before, what reference material a GM finds useful will often be very specific to that GM, and will often change over time. So experiment with different options, and pay attention to the type of information that you had to stop and scramble for (or just really wish you’d had handy) during your last session.

You can also just keep a straight-up stack of Post-Its that you can scribble out transient-yet-important information onto.

This is also works on the other side of the screen, too! If you have visual references for the players (like, say, all those photo handouts that are part of the Alexandrian Remix of Eternal Lies), you could similarly turn them into Post-Its and slap them onto the front of the screen. If you’re going to do this a lot, it might argue for using a simple pattern for the player’s side of your screen. You could even go for a collage approach, where instead of removing the references you just keep layering them on top of each other, creating an ever-evolving visual motif of the campaign that continues to grow as the campaign goes on.

PROVISOS

In my experience, this technique only works passingly well with the old, thin cardboard-style screens. But it works great with the modern, glossy, board-stock screens that have become de rigeur. It works even better with modular screens like those from Pinnacle, Strategem, and Hammerdog.

You don’t want to leave the notes attached for an extended period of time. I first used this technique with my Eclipse Phase screen and I ended up leaving a few swap notes attached when we moved on to other games. When I opened the screen up a couple of years later, I found that the glue had chemically deteriorated and left a chalky residue that was difficult to clean up.

Go to Part 1

Yesterday I rolled out some experimental rules for revising hydras and creating new hydroid creatures. Today we’re going to put them into practice with a few sample creatures.

Bear in mind that this is still an installment of an Untested column: The general rules for hydroids haven’t been tested and these specific monsters even less so. If you do find occasion to use them in your own games, please circle back and let us know how it went!

HYDRALING

Baby hydras — also known as hydralings – are two-headed serpents, only developing the legs of an adult hydra during adolescence. The mothers of hydralings have been seen to deliberately bite off one of the heads from their offspring, prompting the growth of an additional head. Some have hypothesized that this is because hydralings never truly sleep (since one of their heads is always awake), but it’s more likely an instinctual action which prompts (or is prompted by) the hydraling’s development.

HYDRALING
Medium monstrosity, unaligned

Armor Class 13 (Natural Armor)
Hit Points Special
Speed 40 ft., swim 20 ft.

STR 12 (+1)
DEX 15 (+2)
CON 12 (+1)
INT 2 (-4)
WIS 10 (+0)
CHA 6 (-2)

Skills Perception +3, Stealth +4
Senses passive Perception 13
Challenge 1/2 (100 XP)

Amphibious. A hydraling can breathe air and water.

Hydroid. The hydraling has two heads. For every 10 points of damage the hydra suffers, one of its heads dies. If all of its heads die, the hydraling dies.

At the end of its turn, the hydraling grows two heads for each of its severed heads, unless it has taken fire damage since the head was severed. A hydraling can have a maximum of five heads.

Multiple Heads. While the hydraling has more than one head, it has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.

For each additional head beyond one, it gets an extra reaction that can be used only for opportunity attacks.

While the hydraling sleeps, at least one of its heads is awake.

ACTIONS

Multiattack. The hydraling makes as many bite attacks as it has heads.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: (1d4 +2) piercing damage.

TENTACULAR ABOMINATION

A dog-size creature with eel-like skin. It has no head, but its back is a writhing mass of tentacles.

TENTACULAR ABOMINATION
Medium monstrosity, unaligned

Armor Class 15 (Natural Armor)
Hit Points: Special
Speed 30 ft.

STR 17 (+3)
DEX 12 (+1)
CON 14 (+2)
INT 6 (-2)
WIS 13 (+1)
CHA 6 (-2)

Skills Perception +5
Senses Blindsight 60 ft., passive Perception 15
Challenge 3 (700 XP)

Pack Tactics. The tentacular abomination has advantage on an attack roll against a creature if at least one of the tentacular abomination’s allies is within 5 ft. of the creature and the ally isn’t incapacitated.

Hydroid. The tentacular abomination has five tentacles. For every 10 points of damage the abomination suffers, one of its tentacles dies. If all of its tentacles die, the abomination dies.

At the end of its turn, the abomination grows two tentacles for each of its severed tentacles, unless it has taken acid damage since the head was severed.

Multiple Heads. While the tentacular abomination has more than one head, it has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.

For each additional head beyond one, it gets an extra reaction that can be used only for opportunity attacks.

While the abomination sleeps, at least one of its heads is awake.

ACTIONS

Multiattack. The abomination makes as many tentacle attacks as it has tentacles.

Tentacle. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: (1d6+3) bludgeoning damage. The target is grappled (escape DC 13) by one of the abomination’s tentacles. Until this grapple ends, the tentacular horror can’t use that tentacle on another target.

LENGLIAN SERAPHIM

Wings. Dozens of wings clustered together as if shielding a central mass (although no such mass exists within the impossible dimensional toroid of the Lenglian seraph), with eyes opening and shutting between the wings. Some Lenglian seraphs are also known to emit smoke or aurora-like, multi-colored halos as their wings continue to fold and unfold, stretching, reaching, searching, beating the air around them.

(It is also not unusual for Lenglian seraphs to be confused for a swarm of winged creatures, particularly from a distance.)

LENGLIAN SERAPHIM
Large celestial, lawful good

Armor Class 17 (Natural Armor)
Hit Points Special
Speed fly 80 ft.

STR 22 (+6)
DEX 21 (+5)
CON 14 (+2)
INT 21 (+5)
WIS 16 (+3)
CHA 19 (+4)

Saving Throws Wis +7
Skills Perception +7
Damage Resistance Radiant; Bludgeoning, Piercing, and Slashing from Nonmagical Attacks
Condition Immunities Charmed, Exhaustion, Frightened
Senses Truesight 120 ft., passive Perception 17
Languages All, Telepathy 120 ft.
Challenge 12 (8,400 XP)

Innate Spellcasting. The seraph’s spellcasting ability is Charsima (spell save DC 17). The seraph can innately cast the following spells, requiring only verbal components:

• At will: bless, detect evil and good
• 1/day each: augury, commune

Hydroid. A Lengling seraph has thirty-five wings. For every 5 points of damage the seraph suffers, one of its wings is severed. If all of its wings are severed, the seraph dies.

At the end of its turn, the seraph grows two wings for each of its severed wings, unless it has been splashed with unholy water since the wing was severed or is under the effects of a bane spell.

Many Eyed. A seraph has eyes proportionate to its wings. While the seraph has more than one wing, it has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.

For every five wings the seraph has, it gets an extra reaction that can only be used for opportunity attacks.

ACTIONS

Multiattack. The seraphim can make one wing attack for every five wings it has.

Wing. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: (1d8+6) bludgeoning damage.

Radiant Gaze (Recharge 5-6). One creature that the seraph can see within 60 feet of it must make a DC 17 Constitution saving throw, taking 70 (20d6) radiant damage on a failed save, or half as much damage on a successful one.

LEGENDARY ACTION

Can take one legendary action. Only one legendary action can be used at a time, and only at the end of another creature’s turn. Spent legendary actions are regained at the start of each turn.

Buffeting Wings. The seraph beats its wings. Each creature within 10 ft. of the seraph must succeed on a DC 17 Dexterity saving throw or take 1d6+6 bludgeoning damage and be knocked prone. The seraph can then fly up to half its flying speed.

I woke up this morning with a cool idea for how to handle hydras in D&D. A quick check of the 5^th Edition Monster Manual, however, alerted me to the fact that 5^th Edition basically already did it that way.

Well played, 5^th Edition.

Upon further investigation, it became clear that my subconscious had dredged up a goulash of 3^rd Edition, 2^nd Edition, and OD&D mechanics and then regurgitated them.

Which, upon further consideration is a pretty good summary of the design methodology of 5^th Edition. (This is not a critique.)

Hydras, in D&D 5^th Edition, work like this:

Multiple Heads. The hydra has five heads. While it has more than one head, the hydra has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.

Whenever the hydra takes 25 or more damage in a single turn, one of its heads dies. If all of its heads die, the hydra dies.

At the end of its turn, it grows two heads for each of its heads that died since its last turn, unless it has taken fire damage since its last turn. The hydra regains 10 hit points for each head regrown in this way.

The heads give a couple other advantages (extra opportunity attacks, it can sleep while still having one head awake to keep watch), but that’s the fundamental mechanic that models the classic hydra.

There are a couple of changes to this approach that I’d like to experiment with:

1. Eliminate the concept of “total hit points” entirely. You can’t kill a hydra unless you chop off all of its heads.
2. Tweak the mechanic so that you can eliminate more than one head per turn.

So if a fighter gets in there and deals 50 points of damage, his flurrying blades will have hacked off a couple of heads at once. Then maybe the rogue leaps onto its back, deals another 25 points of damage, and hacks off a third head. On the hydra’s turn, it will grow back six heads (two for each severed head).

REVISING THE HYDRA

Thus we can say that a hydra should be mechanically defined as:

• # of heads
• A damage threshold at which it loses a head
• At the end of its next turn or after X rounds it can regrow two heads if it has a severed head
• A sealing condition (usually a type of damage) that prevents
• Dies when it runs out heads.

The “Hit Points” entry of their stat block would be listed as “Special”: They only die if they run out of heads.

Here’s what our revised hydra special abilities would look like:

Hydroid. The hydra has five heads. For every 25 points of damage the hydra suffers, one of its heads dies. If all of its heads die, the hydra dies.

At the end of its turn, the hydra grows two heads for each of its severed heads, unless it has taken fire damage since the head was severed.

Multiple Heads. While the hydra has more than one head, it has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.

For each additional head beyond one, it gets an extra reaction that can be used only for opportunity attacks.

While the hydra sleeps, at least one of its heads is awake.

CREATING HYDROID CREATURES

These mechanics can be used as the basis for other hydroid creatures. Here are some proposed guidelines for doing so.

Damage Threshold. This is the number of hit points required to chop off one of the hydroid appendages. These numbers are loosely based around the idea that a character of the appropriate level should be roughly capable of taking out one head per turn.

I’d recommend halving this value if the sealing damage type or other condition is an unusual one. (This would mean that the killing the monster would typically require killing the heads faster than they can grow back.)

# of Heads. Using the Creating Quick Monster Stats table on p. 274 of the Dungeon Master’s Guide, multiply the minimum hit points for your selected CR by 0.75 and then divide by the damage threshold listed above for its CR.

For example, a CR 10 creature would have 206 hp using the table above, so multiply by 0.75 (154) and then divide by 25 (per the damage threshold table above) to determine that your monster should have six heads.

(This is based strictly on reverse-engineering the existing hydra stat block and it’s unclear if it holds up in practice. It seems to pretty reliably give you 4-8 heads, so you could also probably just get away with slotting in 5-6 heads and not worrying about it.)

You can also use this method to very quickly adapt existing stat blocks. For example, if you wanted to have a hydroid warg (CR ½) you’d take the warg’s current hit point total of 26, multiple by 0.75 (19.5), and then divide by 10. The hydroid warg would start with two heads.

Variant: Maximum Number of Heads. In 2^nd Edition, Lernaen hydras could grow maximum of 12 heads. In 3^rd Edition, they were limited to no more than twice its original number of heads. You might consider doing the same for some hydroid creatures.

DESIGN NOTES

Hydras have a well-known gimmick: They regrow their heads unless you cauterize the stumps with fire. It’s a fun gimmick the can create an encounter which mechanically feels different from other encounters. The only problem is that, because the hydra still has a hit points that’s easier to wipe out than its heads, the mechanical gimmick is irrelevant: There’s often little or no advantage to pursuing it, so parties will just bypass it.

This is boring.

So we fix it by eliminating the bypass. Just like you can’t bypass a troll’s regeneration by just dealing lots of hit point damage to it, you can’t bypass a hydra’s heads.

And, just as regeneration mechanics were created for trolls and now underlie a whole bunch of creatures, these hydroid mechanics can also be used for all kinds of things. We’ll take a look at several examples of this tomorrow.

Go to Part 2

The much delayed Welcome to the Island, a collection of four scenarios for Over the Edge, will be releasing later this month. If you’re looking for scenarios that embody the design principles I talk about here on the Alexandrian, then this is the book you’ve been waiting for. Jonathan Tweet and I have collaborated on a scenario built around the party-planning game structure. The rest of the team, many of whom I originally recruited for Infinity, have created some really fantastic adventures featuring revelation lists, node-based scenario design, and a lot more cool stuff.

Welcome to the Island also features a small selection of what I now refer to as “scenario tools.” I first started developing these back around 2000 or 2001, early in my freelancing career, and have been slowly refining and adding to them ever since. If you’re just prepping notes for your home campaign, these are not things that you’d need (or want) to include. But published scenarios, they help bridge the gap between the author’s imagination and your gaming table. This often takes the form of giving you the tools to integrate a published scenario into your campaign: As writers there’s nothing we can do to avoid making a published adventure generic, but we can make it easier for you to take our generic plug-‘n-play module and make it a seamless part of what you and your players are creating.

These tools usually appear in sidebars. This intentionally segregates them from the main text of the scenario so that they don’t muddy up the presentation of the essential information you need at the table.

GROUNDWORK

Groundwork sidebars are used in scenarios to give examples of how a GM can incorporate elements of the scenario into their campaign prior to running the scenario. The idea is that you can make the scenario feel like an organic part of your campaign by properly laying the Groundwork for it.

We tend not to include anything that’s blatantly obvious. For example, you don’t need us to say something like, “This adventure features NPCs. You could have one of them show up before the adventure begins!” (Unless we have a particularly clever or relevant example of how that might work.)

SCENARIO THREADS

Scenario threads are the mirror image of Groundwork sidebars, suggesting ways in which elements of the scenario could be revisited in later scenarios.

In your home campaign, of course, this is something you should be doing organically: Pay attention to the people or places that particularly resonated with your players. If something interests them or is clicking for them, finding ways to reincorporate it into the campaign is an almost guaranteed success.

PLAYTEST TIP

By the time you’ve finished running a scenario, you’ll often have learned a lot about how you could have used it better. Some of these lessons can be applied in future scenarios, but it’s rare for a GM to have an opportunity to run the same scenario a second time. In published scenarios, though, we have the opportunity to share the insights we’ve gained during out playtests. These Playtest Tips are the “best practices” and offer suggestions for how particular encounters can be handled, alert you to potential problem areas, and try to provide other insights gleaned from our playtesting.

INTERSECTION

This is the newest addition my scenario toolkit and one that I picked up from previous editions of Over the Edge. Intersections reference other published scenarios and suggest how the material in that scenario could be tied to the material in this one. (For example, there’s a strange paranormal gadget in one scenario and a mad scientist in another scenario. When describing the mad scientist’s laboratory, we might include an Intersection that points out you could include a prototype or design notes for the paranormal gadget here, suggesting that this mad scientist was the one who developed it in the first place.)

For Welcome to the Island, these Intersections are limited to other scenarios in the same book. But future anthologies can include references between books, too.

FINAL THOUGHTS

The description of scenario tools in Welcome to the Island also includes revelation lists, which have been discussed here on the Alexandrian as part of the Three Clue Rule. I’d have included adversary rosters, too, but they aren’t used for any of the scenarios in this book. This material, along with the other tools described above, will be repeated in future adventure anthologies for Over the Edge because they weren’t included in the core rulebook. You can contrast this approach with Infinity, where I made sure these tools were described in the core rulebook specifically so that I wouldn’t have to explain them in every adventure we wanted to use them in.

(Which would be all of them, because they’re useful tools.)

I encourage other authors and publishers to also make use of these tools when writing scenarios for publication. They’re incredibly useful and I don’t feel like they should be put in a lockbox.

And if you have any suggestions for other useful tools I could be including in my published scenarios that would make them more useful for you to use at home, please let me know!

Momentum in 2d20 is generated when you roll more successes on an action test than required by the difficulty of the check. These points of Momentum can be spent to either immediately improve the result of the current check or saved to be used in the future, allowing you to build Momentum over the course of several lesser actions until you can accomplish big things.

Momentum can be spent to do stuff like:

• Add +1d20 to future skill tests
• Create obstacles for opponents (generally increasing the difficulty of their skill tests)
• Improve the quality of success
• Increase the scope of success
• Reduce the time required to accomplish a task
• Perform a normally noisy action stealthily
• Take an extra action in an action scene
• Boost damage on an attack
• Get a called shot
• Trigger program effects in Infowar

And so forth.

In Infinity we also specifically emphasized that Momentum is best seen as a creative tool for empowering the players. The GM is also given several structures for making complex rulings around Momentum (see p. 407 of the core rulebook).

One of these is using Momentum to model preparation. If the PCs want to take one action to set up or create advantage on another, the GM can call for a test on the first action (even if it normally wouldn’t require an action test) and then any Momentum generated on that test represents the advantage gained on the primary task.

One of the limitations to this approach, however, is that Momentum ablates over time. At the end of each scene, the team’s pool of saved Momentum is decreased by one. This means that if you want to set up an advantage in one scene that will benefit you for the next scene, it’s difficult to do that.

This problem can be solved by adapting a cool mechanic from Trail of Cthulhu: dedicated pools.

DEDICATED MOMENTUM POOLS

A dedicated Momentum pool can only be used in a given circumstance or in relation to a given subject. For example, you might hack the security cameras in a megacorp’s headquarters, creating a pool of Momentum that can be spent on things like Stealth and Observation tests when the PCs go to infiltrate the HQ.

GMs might also rule that certain resources simply grant a pool of dedicated Momentum. (Perhaps the patron who hired the PCs to steal the megacorp’s new research into captured Tohaa technology simply hands them the access codes to the security cameras as part of their briefing packet. They get the same dedicated Momentum pool even though they didn’t make any skill tests to obtain it.)

There are two advantages to a dedicated Momentum pool.

First, the dedicated Momentum pool does not ablate. The dedicated Momentum pool is separate from other saved Momentum and does not decrease at the end of each scene. This makes a dedicated Momentum pool a great model for preparations that play out over multiple scenes or which are made long before their intended use: The PCs lose some of the utility of the Momentum (since it has to be used for a specific purpose), but in exchange the Momentum becomes more durable.

Second, the dedicated Momentum pool can also create unique vectors that allow the PCs to take actions that they otherwise couldn’t. If you have access to the security feeds, for example, you can check them for activity in other areas of the building. If you have a copy of the religious text of an extremist Morat cult, you can reference it for information about their rituals that you would otherwise have no way of knowing.

These vectors can cut both ways, though! When the Momentum from the security camera pool runs out for example, it could easily justify the GM spending Heat to generate a complication in the form of the megacorp’s hackers realizing their system has been compromised and launching an Infowar attack on the PCs.