Skeleton Berserker

Haste, Rend (when this creature deals damage to another creature, that creature's controller loses
that much life.)
{b}: Regenerate this creature. If this creature has
been regenerated before in this manner, sacrifice
it at the start of your next upkeep.
Pay 2 life. Cast Skeleton Berserker from your graveyard. The next time Skeleton Berserker
would be put in the graveyard, exile it.