I already got one for them -- The Bowellrog.
Legolas turned and set an arrow to the string, though it was a long shot for his small bow. He drew, but his hand fell, and the arrow slipped to the ground. He gave a cry of dismay and fear as he doubled over. "Ai! ai!" wailed Legolas. "A Bowellrog! A Bowellrog is come!" Legolas scampered off into a dark corner with both hands at his stomach. Presently a sound like the rending of a great canvas mixed with that of a maxed-out Harley chopper filled the room, and a black smoke swirled in the air. Gimli stared with wide eyes. "Durin's Bane!" he cried, and letting his axe fall he convered his face. "A Bowellrog," muttered Gandalf. "Now I understand." He faltered and leaned heavily on his staff, burying his face in his sleeve. "What an evil fortune! <blrp!> What a stench!!! And I am already weary." Boromir fell to the floor, heaving. Aragorn fell back against a wall. Frodo, Sam, Merry and Pippin all fled the chamber. Even the orcs recoiled, as if they themselves were afriad. "Bad Lembas!" cried Pippin as he stumbled and fell on his face. And Legolas' searing cry of heart-rending torment burned into the ears of all still left in that accursed chamber. "AAAHHHHH MY ASS!!!!!!!!!" --- Then Aragorn recounted all that had happened upon the pass of Caradharas, and in the days that followed ... and the coming of Terror. "An evil of the ancient world, it seemed, such as I have never smelt before," said Aragorn, turning a shade of pale green. "It was both a shadow and a flame, strong and terrible." "It was a Bowellrog of Morgoth," said Legolas; "of all elf-banes the most deadly, save the One who sits in the Dark Tower." He felt at his stomach. "Ohhh..." "Indeed I smelt that which haunts our darkest dreams, I smelt Durin's Bane," said Gimli in a low voice, and dread was in his eyes. Legolas' face took on a new countenance of alarm and he rushed from that place. Soon his anguished cries could be heard, piercing the air as one of his arrows. "Alas!" said Celeborn. "Had I known I would have forbidden you to pass the northern borders, you and all that went with you." A foul cry and series of oaths sounded in the distance. "Sounds like someone is indeed passing the northern borders, complete with trees and rocks!" said Pippin just moments before Aragorn cuffed him.