Move: 5 feet/turn
Hit Dice: 1 HD per tentacle
Armor Class: 9
Treasure Type: M x 3
Attacks: 3 tentacles
Damage: 0 (see below)
These dungeon-dwellers are actually carnivorous plants distantly related to bladderwort. Adapted to life in the dark, they lurk in pits, chimneys, closets and other small spaces, reaching silently for passersby with three thirty-foot-long tentacles (surprise on 1-4 in 6). Each tentacle attacks independently as a 1 HD monster, and on a successful hit grabs the target but does no immediate damage. If the captured character is holding a weapon, a successful 3d6 dexterity check indicates that the weapon arm remains free and able to attack. On the next round, the victim will be dragged into the monster's central mouth and take 2d6 points of damage per round thereafter. Each tentacle can take 1 HD of damage before being destroyed, and the creature will die rapidly from loss of fluid if it loses all of its limbs. Green Grabbers do not normally move about, but if necessary can pull themselves along slowly with their tentacles to a new hiding spot.
Periodically the monster enters a flowering phase, called Sleepflower, in which the tentacles are weaker but have a large yellow flower at each end. These flowers produce a blood-like nectar that attracts stirges, which pollinate the plants while feeding. In this form the plant protects itself with its pollen. If approached, the monster will extend a tentacle with a yellow flower that opens and sends out a puff of pollen in a 5' area. Any character in this area must Save vs Poison or fall asleep for 1d6 turns. Each flower can send 3 puffs of pollen per day.
They do not hoard treasure, but are occasionally found with incidental treasure (such as a handful of coins) from previous victims.
|Bladderwort Traps, picture from Wikipedia|
Edit: I also checked on the mobile plants I remembered from Holmes' other stories:
In "The Adventure of the Giant Chameleon" (A&E #14, 8/76) they are described as having "big open flowers and moving tentacles" - which fits well the Green Grabber. In that story the plants are growing in a chasm in a underground cavern lit by a luminescent green glow.
In Maze of Peril, near the end of chapter 1, there are mobile carnviorous plants that snap their "spine-fringed jaws like a startled starfish" in a floral room in the dungeon but lit by sunlight from above. These seem more like Venus-fly trap type plants.
See also Tony's comment about the tentacle roots in "In the Bag".