"First, he pointed that giant metal rod at me and out came a glass vial, it exploded next to me! Next thing you know, out comes a friggin’ bear! Then, as if that wasn’t bad enough, he sticks it in the ground. It expands and he walks into it to get a snack!" - Xzud, Experimental Arms Dealer.
A slow, stupid creature that crawls onto people and latches onto them, often on feet, hands, and other extremities, numbing down the area and slowly feeding on it. It's easy to avoid while awake, but nearly impossible to remove once attached. Many an adventurer has been forced to hack off an arm or leg after waking with a Stoneleech wrapped around it. Sleep with one eye open! (This idea came from "Wizard's Rule")