10. Kalibak - Superman: Dark Side #1/ Injustice: Year One #24
Of all the various immortal DC villains, Kalibak is perhaps the single most unfortunate of them.
This is because - though he's seldom a major villain in any storyline - he's died twice in various series and spin-offs, despite being supposedly immortal.
The first of these deaths comes in the ever under-estimated Superman: Dark Side series, where we see a version of the Man of Steel who is loyal to Darkseid, and murders Kalibak in order to appease his bloodthirsty master.
For Injustice, however, matters are significantly more simple. In issue #24, Kalibak attempts to invade Earth with his forces, seemingly unaware of the fact that this universe's Superman is one who is not going to put up with that kind of tomfoolery. So unwilling, in fact, that he slam dunks the villain into the ground with enough force to destroy his Apokalypian cranium, putting Darkseid's son down like a particularly heavy and cunning basketball.