A trashed Champ Valk is my vote. Great flip disc and more versatile than my second choice, a trashed Champ monarch b/c it's a one trick pony. It only does runaway turnovers that will not fade back.
My Valk won't come back either if I release it flat but if I put a little hyzer on it, it'll jump on that anny line for a long time and just fade back a little at the end for nice bombs.