What kind of worm is this

don't really know if its a work, a caterpillar or a centipede.
but its lime green, its hard, and about the size of a pinky (finger)
when it bite me, it felt like an electric shot when to my finger (sorry, dont know how to explain how it felt) could anyone help me figure it out.

if it looks like this: http://upload.wikimedia.org/wikipedia/en…
its a tomato hornworm.