Catepillar or is it Callepitter?

Depends on who's saying it, but anyway it's the reason my husband lets milkweed grow in our flower bed. It's so we can have guys like this come along and make themselves at home. This guy is awesome. We should name him. The Brown boys were here looking him over, so maybe I'll send them a call out for suggestions. (if they're anything like their parents, we'll get some doozies!!!) He is hanging head downward for some reason. I hope he decides to stick around for a while so we can see what happens to him!!!