The honeytrap is a roper-like creature which relies on deceit and camouflage to trap its prey. The upper half of its body bears the appearance of a beautiful young maiden, but this beauty is 
wrapped around a mass of tentacular horror.
Quicksand Hunter. The honeytrap’s favored tactic is to secrete a corrosive chemical capable of rendering even solid rock into a quicksand-like liquescence. When its prey draws near, the honeytrap will cry in terror and plead for their aid. It will wait until they are at their most vulnerable before striking: Its sternum will part into a ravenous maw, exuding a half dozen coiled tentacles which will burst forth and wrap themselves lethally around the honeytrap’s would-be saviors.
Tentacular Chase. The honeytrap prefers to lure its victims into a dangerous mixture of complacency and chivalry before striking, but those seeking to flee a ravenous honeytrap may be shocked as it wrenches itself free from its muck-ridden hunting grounds and pursues them with great speed upon a second tumultuous mass of tentacles extruding from its “maiden” waist.
More startling even than that diabolic chuckle was the scream that rose at my very elbow from the salt-compounded sand – the scream of a woman possessed by some atrocious agony, or helpless in the grip of devils. Turning, I beheld a veritable Venus, naked in a white perfection that could fear no scrutiny, but immersed to her navel in the sand. Her terror-widened eyes implored me and her lotus hands reached out with beseeching gesture.
The Abominations of Yondo, Clark Ashton Smith
HONEYTRAP
Large monstrosity, chaotic evil
Armor Class 18
Hit Points 119 (14d10+42)
Speed 40 ft.
STR 19 (+4), DEX 13 (+2), CON 17 (+3), INT 12 (+1), WIS 11 (+0), CHA 17 (+3)
Skills Athletics +7, Deception +6, Persuasion +6, Stealth +5
Senses darkvision 60 ft., passive Perception 10
Languages Common, Elven
Challenge 8 (3,900 XP)
Proficiency Bonus +3
Grasping Tendrils. The honeytrap has six tendrils. Each tendril can be attacked (AC 18; 20 hit points; immunity to poison and psychic damage). Destroying a tendril deals no damage to the honeytrap. A tendril can also be broken if a creature takes an action and succeeds on a DC 16 Strength check against it.
Quicksand Liquiescence. A honeytrap can turn a 10 ft. radius of earth, dirt, or stone into quicksand in 1d4 minutes by excreting a powerful, acidic chemical. If a honeytrap is slain, moves, or stops excreting the chemical, the ground will re-solidify within 1d4 hours.
A creature entering quicksand sinks 1d4+1 feet and becomes restrained. At the start of each of its turns, the creature sinks another 1d4 feet. Creatures in quicksand can attempt a DC 10 + the number of feet it has sunk Strength check to escape. This check is made with advantage if they have hold of a rope or similar item attached to something out of the quicksand.
A creature completely submerged in quicksand cannot breathe and begins to suffocate. They are also no longer able to escape the quicksand without assistance.
A creature outside can pull a creature out of quicksand as an action with a DC 5 + the number of feet the target creature has sunk into the quicksand Strength check.
ACTIONS
Multiattack. The honeytrap makes six attacks with its tendrils, uses Reel, and makes one attack with its bite.
Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 31 (6d8+4) piercing damage.
Tendril. Melee Weapon Attack: +8 to hit, reach 30 ft., one creature. The target is grappled (escape DC 15). Until the grapple ends, the target is restrained and has disadvantage on Strength checks and Strength saving throws, and the honeytrap cannot use the same tendril on another target.
Weakness. A honeytrap’s strands sap an opponent’s strength. Anyone grabbed by a strand must succeed on a DC 15 Constitution saving throw each round or suffer a level of exhaustion.
Reel. The honeytrap pulls each creature grappled by it up to 15 ft. straight toward it.
I know it’s an old trope that it should be a “maiden”, but why not add a psychic ability that the Honeytrap can use to morph its features into whatever would elicit the best response?
Seconding Alistair. A doppelganger-like disguise ability, so it can look like an absent party member or a hapless loved one, would be a nice detail.
I like that idea.
I do see from where y’all are coming from – allowing the monster to project a male victim would acknowledge the possibility of female heroes (as well as homosexual male ones of course).
Not sure this is an improvement, however. But first let me say: it’s your game, do what you will with it!
To me, though, the monster evokes very classic (or old-fashioned if you will) tropes where men are from Mars and women are from Venus, as immortalized by the great fantasy artists such as Frank Frazetta, Sanjulien and others.
In this context, it makes perfect sense for the monster to project a female form that is a) helpless and b) alluring, since “natural selection” for any organism whose main diet includes heroes would have benefited plants with this bait.
Of course you can easily say “but magic” and have this plant do whatever you want. Myself, I choose to understand and support the Alexandrian’s choice to stick to the basic trope for the aforementioned reasons.
PS. I do not wish to insult the reader’s intelligence, so of course the real reason is not the abovementioned faux-scientific bullshit ones. Instead I simply ***like*** to sprinkle the naked female form into my stories, as I am sure Clark Ashton Smith and his readership did! Your mileage may vary 🙂