This clever loop creates an engine by turning free resources into endless triggers, beginning with Bartolomé del Presidio to feed on your creatures. By sacrificing the 0-mana Phyrexian Walker, you trigger Mortuary to immediately tuck the artifact creature back onto the top of your library rather than letting it stay in the graveyard. Meanwhile, Gwenom, Remorseless is attacking to let you peek at and cast spells from the top of your library, paying its zero mana value with life instead of mana. Because Phyrexian Walker costs zero to cast, you can endlessly replay it, sacrifice it again to pump Bartolomé del Presidio, and repeat the cycle for infinite storm count, sacrifices, and death triggers.