Only spotted in the Hollow Bough, the aptly named Stabber Vine is very aggressive and should be approached with caution. The source of these "vines" is still unknown as is their exact nature. Is it a plant or animal, we just don't know.
— Miner's Manual Description
The Stabber Vine is a hostile form of life encountered only in Hollow Bough. It is an aggressive and much more dangerous form of its stationary brethren and actively attacks dwarves.
Stabber Vines spawn in clusters of 3 in the same spot and have quite a large range. If a player wanders near, one of the clawed vines will slowly aim at them, then lash out with lighting speed and impale them, dealing heavy damage. If the dwarf stays in the Stabber Vines' range, they will alternate attacking with the other claws. Players can attack Stabber Vines to destroy them: destroying the yellow bulb on a vine will kill that vine, and destroying the base of the vines will destroy all of them at once.