t: add b.
whenever a creature you control dies, put a corpse counter on crowded crypt.
4bb, t, sacrifice crowded crypt: create a 2/2 black zombie creature token with decayed for each corpse counter on crowded crypt. (a creature with decayed can't block. when it attacks, sacrifice it at end of combat.)
Crowded Crypt from Commander: Innistrad: Midnight Hunt