Ashnod's Altar + Geralf's Messenger + Intruder Alarm + Skeleton Ship

UB identity

Commander legal

The 4 combo pieces

What must be in place

Skeleton Ship does not have summoning sickness.
Geralf's Messenger does not have any +1/+1 counters.

How to execute it

  1. Activate Ashnod's Altar by sacrificing Geralf's Messenger, adding {C}{C}.
  2. Geralf's Messenger dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
  3. Geralf's Messenger enters the battlefield, triggering itself and Intruder Alarm.
  4. Resolve the Geralf's Messenger trigger, causing an opponent to lose 2 life.
  5. Resolve the Intruder Alarm trigger, untapping all creatures.
  6. Activate Skeleton Ship by tapping it, putting a -1/-1 counter on Geralf's Messenger.
  7. Repeat.

What the combo produces