In the Nineties this monstrosity killed Superman. He was bought to the small screen in Season 8 of Smallville (and they got the look spot on). The characters roots are on Krypton, where a scientist created the beast to survive on Kryptons barren wastelands. Since Man of Steel spent so much time exploring Krypton, this enemy would not be out of place in DCs shared universe. He possesses incredible levels of strength, and he has bone-like claws which protrude from all over his body. These claws are capable of cutting Superman, and in his final showdown with Kryptons last son he pretty much levelled Metropolis. If that wasnt enough for you, each time he is killed he comes back immune to that form of death; this means that he is both more dangerous and can be used in future films even after being defeated by the Justice League. In the comics he does kill Superman, so die-hard fans would probably want to see this happen (or at least referenced) on screen. Would this work? Perhaps Doomsday would best be left for when Henry Cavill no longer plays Kal-El. However, the great thing about Doomsday is that he can be bought back from the dead, meaning that this possibility is always open.