[@Savato]
.... ZOMBIE DOOMSDAY!

Sorry, had to get that out there.

But yeah, Apocalypse can adapt to pretty much anything he's exposed to. He can even copy the powers of those he fights. If the Ethereal makes the mistake of killing/fighting him too often, he'd eventually learn to use psionic powers. He copied Superboy's tactile telekinesis, cyborg superman's hacking abilities, steel's nanites, and he even managed to adapt to and control the Phantom Zone.