Reassembling Skeleton + Phyrexian Altar + Pawn of Ulamog

Reassembling Skeleton

Phyrexian Altar

Pawn of Ulamog

How it works

1. Activate Phyrexian Altar by sacrificing Reassembling Skeleton, adding
2. Pawn of Ulamog triggers, creating a 0/1 Eldrazi Spawn creature token with "Sacrifice this creature: add C"
3. Activate the Eldrazi Spawn by sacrificing it, adding C.
4. Activate Reassembling Skeleton by paying 1, returning it from your graveyard to the battlefield tapped.
5. Repeat.

This loop is a classic masterclass in self-sustaining necromancy, seamlessly recycling a single skeleton to feed an insatiable altar. By sacrificing Reassembling Skeleton to Phyrexian Altar, you generate the black mana needed to bring it right back from the graveyard, while simultaneously satisfying Pawn of Ulamog's trigger condition whenever it dies. That trigger grants you a bonus Eldrazi Spawn token, which can then be sacrificed to the Altar for the colorless mana required to complete Reassembling Skeleton's activation cost.