Out of Africa?

What the hell is that? It was like s fat, green cigar, wriggling it's way through our yard at a rate of knots. I assume it's a caterpillar of some sort. My vague recollection of secondary school biology tells me, if it is, it will ultimately metamorphose into some sort of bug. I'm not sure I want to see the bug that comes from that. Especially if it flies.
I didn't want to kill it so I scooped it up and put it in the gutter - near the neighbor's yard. It's a survival of the fittest thing - if it makes it back into a yard, it won't be mine.