Tenacious Dead | Altar of Dementia | Pitiless Plunderer

(and two other cards)

Sacrifice
Tenacious Dead to
Altar of Dementia, milling target opponent for 2.
Sifter of Skulls,
Pitiless Plunderer,
Blood Artist, and
Tenacious Dead trigger; stack the triggers to resolve in that order.
Sifter of Skulls generates an Eldrazi Scion token; sacrifice it to float ({1} magic symbol) (
Pitiless Plunderer and
Blood Artist trigger again).
Resolve two
Pitiless Plunderer triggers, generating two Treasure tokens; crack one to float ({B} magic symbol) .
Resolve two
Blood Artist triggers, draining opponent for 2.
Resolve the
Tenacious Dead trigger, paying ({1} magic symbol) ({B} magic symbol) to return it to the battlefield from the graveyard.
Repeat the sacrifice-recursion loop, gaining one Treasure token per loop and draining opponent infinitely with
Blood Artist triggers.