Gruck, Ruler of Bones

The first card that enters your graveyard each
turn gains relapse as it enters the graveyard.
Whenever one or more cards leave your graveyard, create a 1/1 black Skeleton creature token.
{t}, Sacrifice a skeleton you control: Creatures you control gain menace until end of turn.
By the time you hear the rattling bones, you're next to
join their ranks.