whip scorpion

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various nonvenomous arachnids of the order Uropygi (or Thelyphonida), such as the vinegaroon, that have large pedipalps and a slender whiplike process at the tip of the abdomen.

from The Century Dictionary.

• noun A false scorpion of the family Thelyphonidæ, having a long, slender abdomen like the lash of a whip, as Thelyphonus giganteus, of the southern United States: also there called grampus, mule-killer, and vinaigrier.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun nonvenomous arachnid that resembles a scorpion and that has a long thin tail without a stinger
• noun nonvenomous arachnid that resembles a scorpion and that has a long thin tail without a stinger