Putrescent Knight

Trample.
Whenever a creature dealt combat damage by Putrescence Knight this turn dies, exile that card. It perpetually gains the Skeleton creature type.
Whenever Putrescent Knight deals combat damage to a player, you may return any number of Skeleton creature cards with a combined mana value equal to or less than the damage dealt from either your graveyard or from exile to the battlefield.
Putrescent Knight's power and toughness are each equal to the number of Skeleton creature cards in your graveyard