Infinite death triggersInfinite creature ETBInfinite lifelossInfinite creature LTBInfinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite scry 1Infinite untap of creatures
How it works
Activate Viscera Seer by sacrificing Geralf's Messenger.
Geralf's Messenger dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Geralf's Messenger enters the battlefield, triggering itself and Intruder Alarm.
Resolve the Geralf's Messenger trigger, causing an opponent to lose 2 life.
Resolve the Intruder Alarm trigger, untapping all creatures.
Resolve the Viscera Seer ability from step 1, causing you to scry 1.
Activate Skeleton Ship by tapping it, putting a -1/-1 counter on Geralf's Messenger.