This loop turns Phyrexian Altar and Missy into an infinite recycling engine for your graveyard, fueled entirely by the mana generated from sacrificing your creatures. When you sacrifice Ire Shaman to the Altar, Missy's triggered ability instantly catches it, resurrecting it back to the battlefield as a face-down 2/2 Cyberman artifact creature. You then use that exact red mana to pay for Ire Shaman's morph cost, turning it face up and triggering its exile ability before feeding it right back to the Altar.