Kullmawger, the Demon Heart

Flying
Demonize (Whenever this creature blocks a
creature, it gets +X/+0 until end of turn where
X is equal to half its toughness rounded up.)
At the beginning of your upkeep, if a creature
you controlled died last turn, search your library
for a card with converted mana equal to that creatures toughness and put it into your hand,
then shuffle your library.