My Little Pony: Friendship is Magic - Sombra is 2deep4u

He's been shown to be able to grow from small bits of himself, so his horn could be a foreshadowing of him returning in another episode. Or it could just be a kid-friendly way to show the badguy getting ripped apart alive. Either one.

But being absolute on the matter isn't correct either. He COULD be dead, and he COULD be alive. He's Schrödinger's pony at the moment.

Sombra is an underrated villain for sure. Who knows what would've happened if he tried to take over Ponyville, Canterlot, and all of Equestria.