Fan Casting Doctor Doom back from the dead in Fantastic Four: Enter Namor (2009)

Namor had found Doom's body floating in his ocean. So, his men grabbed him and have used whatever means necessary to bring him back to life, and breathe underwater. Revived, Doom asked Namor why he is here. Namor asked the same. Doom explained he almost destroyed his enemies, the Fantastic Four. Namor now believes he and Doom have a common enemy. Doom also learns how Namor gets his power, and a smile comes on his face. He proposes a deal to destroy the Fantastic Four together. Namor and Doctor Doom shake hands, forming an alliance.