Infinite creature LTBInfinite creature ETBInfinite creature sacrifice triggersInfinite death triggersInfinite mana creatures you control can produceInfinite untap of creaturesInfinite surveil
How it works
Activate Xu-Ifit by tapping it, returning a creature card from your graveyard to the battlefield.
When the creature enters the battlefield, Intruder Alarm triggers, untapping all creatures.
Activate Umbral Collar Zealot by sacrificing the creature returned in step 1.
Repeat.
This crafty graveyard loop revolves around Xu-Ifit, Osteoharmonist constantly pulling a creature card back from the graveyard, utilizing its ability to cheat a body directly onto the battlefield at sorcery speed. The magic truly happens thanks to Intruder Alarm, which turns that entry into a global untap event that readies both Xu-Ifit, Osteoharmonist and any other creatures you control. To keep the cycle going, Umbral Collar Zealot acts as the necessary sacrifice outlet, feeding the freshly returned creature back into the graveyard while letting you surveil along the way.