Activate Phyrexian Altar by sacrificing Reassembling Skeleton, adding .
Activate Reassembling Skeleton by paying 1, returning it from your graveyard to the battlefield.
Imotekh's first ability triggers, creating two 2/2 Necron Warrior artifact creature tokens.
Activate Phyrexian Altar by sacrificing a Necron Warrior, adding 1.
Repeat.
This loop transforms the humble Reassembling Skeleton into an endless engine of creation, fueled by Phyrexian Altar's sacrificial mana. Thanks to Encroaching Mycosynth turning all your permanents into artifacts, Imotekh the Stormlord watches the Skeleton leave your graveyard and rewards you with a pair of Necron Warrior tokens every single time. You can then sacrifice those freshly minted tokens to the Altar to generate the exact mana needed to bring the Skeleton back, netting a growing army of artifacts and infinite mana in the process.