36 years ago - Irwin Schwab is born.
11 years ago - 25-year-old Irwin somehow becomes Ambush Bug?
Ambush Bug was conceived as a deliberately goofball character that served as an occasional pop-in superman villain before he started being used as fourth wall breaking comedy character, operating in the self-serious world of comic book superheroes but using a self-aware Bugs Bunny-esque sensibility. You might recognize this as the exact same formula that catapulted Marvel's Deadpool to levels of popularity that border on the ridiculous.
Of course, Ambush Bug doesn't murder people, so perhaps that was the missing element. Instead, he's a reality-hopping teleporter that is one of the only characters within DC's lexicon that is actually self-aware enough to comment on the constant tectonic shifting of their continuity, and therefore is regularly used as a reporter in their efforts to explain the latest timeline mashup boogaloo. His own stories are generally just wacky absurdist good times, and no attempt is ever made to try to normalize the character, as that would be completely missing the point.
Of course we used him. We're trying to keep out timeline free of the ridiculous multiple-reality hijinks, but we'd still want the character to basically be a Looney Tune. To that end, we're not bothering to describe who he is or where he got his powers, just that it happened at all. From there, he's free to pop in and out of stories and generally confuse everyone.