I had no idea who or what Ambush Bug was...
I would have to assume that he's a Bronze Age character, and maybe a parody of Superman, judging from the costume he's got on. The exact origin and background is profiled here.
It's strange, I'd only heard about Ambush Bug, knowing very little other than that, but now, as I can see, he's not that old a creation, and Keith Giffen, Robert Loren Fleming and Paul Kupperberg are the creators. They created him around the early 80s, the time when Giffen first began his own career. His real name may be Brum El (on earth, it's Irwin Schwab), and is an alien from another planet, not unlike Superman, whose own books Schwab first appeared in in backup stories.
It's certainly good to get to know a bit about who Ambush Bug is now, that's for sure!