"What's that clicking noise?" Allianora paused and looked around the thick undergrowth. Something stung her face, and she screamed, flinging herself back. From out of the underbrush hooked maws and chitinous legs swarmed forward.
Rathgar grabbed Allianora and tossed her behind him, while bashing his shield against one of the creatures. Feris caught her and pulled her away while Nimble lashed out with his blade, cutting off one of it's legs. A black fluid squirted out, and the creature flinched away. Nimble heard the crash off to the side a moment before he felt the bite, and the legs of the thing grab hold of him.
"Move faster Rathgar!" Feris yelled, slamming his staff on the ground, and instantly everyone slowed down. Easily sidestepping the lunging bite of the nearest creature, he brought his sword down hard, nearly cleaving it in two. A drawn out scream caused him to turn to see Nimble being dragged up into the branches. Rathgar charged forward, slicing his blade up above Nimble's head, cutting deep into it's armored body. Nimble fell from it's grip, and landed in a crouch.
Armor Class: 6
Hit Dice: 3+2* (M)
Move: 120' (30')
Attacks: 1 bite or 1 spit
No. Appearing: 0 (2d4)
Save As: F4
Treasure Type: none
XP Value: 75
Monster Type: Lowlife (Common)
These multi-legged centipede-like creatures can reach a total length of over 15'. They are usually found in dense forests, living in the undergrowth and hunting for prey. In spite of their size, they are adept at hiding, and in their natural habitat will surprise they're prey 5/6 times. Their first attack is usually to spit poison at the nearest opponent(save vs wands or be blinded for 1d4 rounds), and then to move in and bite them. A successful bite will automatically latch on, and the thorn crawler will attempt to drag away their victim. Only by causing the thorn crawler damage will it release its victim.
Image Source: One of my Thorn Crawler minis from Mage Knight by WizKids.