Giffen's swipes go back to his peak period work on LEGION. Even before the Great Darkness Saga (LEGION 290-294) Giffen was visibly swiping pages from
LONE SLOAN/DILIRIUS by Phillippe Druillet that was serialized in HEAVY METAL in the late 70's.
Starting in 1984, Giffen's art dropped off a cliff in quality, and he was swiping pages from Toth and Munoz. But when the art was not as beautiful and detailed as during his 1982-1983 LEGION period, I think readers began to abandon him. Lots of artists swiped Neal Adams (Buckler, Grell, Brunner, Sienkiewicz, to name just a few) and their careers don't suffer for it. Giffen had the added detriment that his new work really, REALLY sucked, and fans stopped buying it.
The later AMBUSH BUG mini-series work likewise was a decline from the above stories I listed. They were less funny, and just became annoyingly silly. The earlier Ambush Bug stories in DC COMICS PRESENTS and ACTION COMICS were playful, but also struck the right balance. Others may have loved the miniseries, but an issue or two in, that's when I got off the train.
