A Roper stands 9 feet tall and tapers from 3 or 4 feet in diameter at the base to 1 foot across at the top. It weighs 2,200 pounds. A roper has 60-foot Darkvision and its coloration and temperature changes to match the features of the surrounding cave. It hunts prey by standing very still and imitating rock. This tactic often allows the roper to attack with surprise. When prey comes within reach, it lashes out with its strands. In melee, it bites adjacent opponents with its powerful maw.

If a roper hits with a strand attack, the strand latches onto the opponent’s body. This deals no damage but drags the stuck opponent 10 feet closer each subsequent round unless that creature breaks free (requires an open doors check). If a roper can draw in a creature within 10 feet of itself, it will bite with a +4 attack bonus in the same round. A strand has 10 HP and can be attacked instead of the body of the roper. If the strand is currently attached to a target, the attacker takes a -4 penalty on its attack roll. Severing a strand deals no damage to the roper itself.

Ropers are cavern-dwelling monsters and are frequently mistaken for stalagmites. These monsters are grey-green in colour, standing around 8-ft to 12-ft tall, with a hide that mimics the smooth limestone formations of a natural cavern.

Ropers are about 3-ft to 4-ft at the base and approximately 1-ft wide at the apex. These monsters are almost always encountered in their stalagmite shape but can alter their appearance to some degree. A roper can assume the shape of a pillar, a boulder, or flatten themselves and lie flat to appear as no more than an irregularity on the walking surface of the cavern floor. It can also cling to a cavern ceiling (or wall) and appear as a stalactite. Through means of tiny adhesive cilia on its underside, the roper can move slowly and these cilia are what allow it to cling upside down to the ceiling.