*nightcrawler*

n. A terrestrial worm that burrows into and helps aerate soil; an earthworm. It often surfaces when the ground is cool or wet, and is used as bait by anglers. The term is used mostly in the northern and western U. S.
Syn. -- earthworm, angleworm, fishworm, fishing worm, wiggler, nightwalker, dew worm, red worm. [ WordNet 1.5 ]