Green Bug Invasion

We see butterflies all the time, so it only stands to reason that they have to come from somewhere.............who knew it was our Virginia Creeper plant? This is actually the second caterpiller we saw, but I didn't get a picture of the first one. It looked just like this........only a kind of pinkish rust color. Been googling around and trying to figure out what kind of butterfly this will turn into, but don't know for sure yet.

Good fun to freak the neighbor boys out with this bug too.........