Ambush Bug appears to be insane and unable to tell the difference between reality and fantasy and as a result not too much is known about him. What little we do know, which may or may not be true, is that one day an intergalactic laundry shipment from a doomed planet crash landed on Earth and was found by Irwin Schwab, who adopted the costume and became known as Ambush Bug (Act No. 563, Jan 1985: "Black Beauty!").
In December 1982, Ambush Bug reveals himself as a villain and murders a man on live television. Superman and the Doom Patrol go after Ambush Bug to bring him to justice. When they try, Ambush Bug just runs around teleporting and acting like a goofball trying to get away before being captured (DCCP No. 52, Dec 1982: "Negative Woman Goes Berserk!").
In July 1983, Ambush Bug becomes obsessed with Superman and thus follows along as the Man of Steel time-travels to the 30th Century, home of the Legion of Super-Heroes. Superman, not wanting to deal with this pest decides to leave him with the Legion of Substitute Heroes. However, after Ambush Bug makes a mess of things, Superman must return to capture him once again (DCCP No. 59, Jul 1983: "Ambush Bug II!").
Ambush Bug breaks out of a prison van and runs into Supergirl, who he mistakes for Superman. He decides to go straight and become a super-hero and begins to fight crime in his own wacky way until he is captured by Supergirl and is returned to jail (SG2 No. 16, Feb 1984: "Bug-Out!").
In March 1985, Ambush Bug decides to pay a visit to Superman, Batman and Wonder Woman, in order to try to convince them to guest-star in the first issue of his upcoming miniseries and of course, they all decline (Act No. 565, Mar 1985: "$ellout or Manna from Mando!").
In May 1985, in order to make amends for his past mistreatment of Superman, Ambush Bug decides to give him a present in the form of beautiful red gem. This "gem" turns out to be Red Kryptonite, the effects of which cause Ambush Bug and Superman to switch bodies (DCCP No. 81, May 1985: "All This and Kobra Too!").