Yerkin Berkin Sloog

0: Whenever a creature card enters an opponents graveyard from anywhere choose 1: Gain 1 life / Lose life = the CMC and create a token copy of it.
+1: Create either a 1/1 Skeleton token with Reach, a 2/2 Zombie token with Vigilance, or a 1/2 Bloodspawn token with Unblockable.
-4: Create a Spell Slot Artifact that says "Pay 1 colorless, 1 blue, and tap this card to counter target instant or sorcery spell."