Sacrifice Bile Urchin to have target opponent lose 1 life.
Tap 5 untapped zombies you control to return Bile Urchin to the battlefield.
Intruder Alarm triggers, untapping all creatures.
Repeat.

Infinite death triggers

Infinite ETB

Infinite lifeloss

Infinite LTB

Gravespawn Sovereign

Bile Urchin

Intruder Alarm

Activate Bile Urchin by sacrificing it.
Bile Urchin dies, triggering Salvaging Station and Kaya's Ghostform.
Resolve the Salvaging Station trigger, untapping it.
Resolve the Kaya's Ghostform trigger, returning Bile Urchin from your graveyard to the battlefield.
Resolve the Bile Urchin ability from step 1, causing target player to lose 1 life.
Activate Salvaging Station by tapping it, returning Kaya's Ghostform from your graveyard to the battlefield attached to Bile Urchin.
Repeat.

Infinite sacrifice triggers

Kaya's Ghostform

Salvaging Station

Encroaching Mycosynth

Combos with "Bile Urchin"