Activate Yahenni by sacrificing Reassembling Skeleton.
When Reassembling Skeleton dies, Pitiless Plunderer and Golgari Germination trigger, creating a creature token and a Treasure token.
Resolve the Yahenni ability.
Activate Yahenni by sacrificing the creature token.
When the creature token dies, Pitiless Plunderer triggers, creating a Treasure token.
Resolve the Yahenni ability.
Activate the Treasures by tapping and sacrificing them, adding 1.
Activate Reassembling Skeleton by paying 1, returning it from your graveyard to the battlefield.
Repeat.
This clever loop feeds on the constant cycle of death and rebirth to build an unstoppable threat. Whenever you feed Reassembling Skeleton to Yahenni, Undying Partisan, the persistent skeleton leaves behind a trail of value: Pitiless Plunderer converts the sacrifice into a Treasure token to help fund the skeleton's return, while Golgari Germination sprouts a 1/1 green Saproling creature token to fuel Yahenni's hunger even further. By cycling the Skeleton and the generated tokens through the sacrifice altar, Yahenni grows indefinitely with +1/+1 counters while easily generating infinite death, artifact, and creature triggers.