How can you create a combo with Skeleton Ship, Intruder Alarm, Geralf's Messenger, Ashnod's Altar?
user
[START OF COMBO]This combo can be formed with Skeleton Ship, Intruder Alarm, Geralf's Messenger, Ashnod's Altar

Color identity: UB
Mana cost: 
Steps:
  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.[END OF COMBO STEPS]

Result:
  - Infinite colorless mana
  - Infinite death triggers
  - Infinite enters the battlefield
  - Infinite lifeloss
  - Infinite leaves the battlefield
  - Infinite mana creatures you control can produce
  - Infinite sacrifice triggers
  - Infinite untap of all creatures[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - All permanants must be on the battlefield
  - Skeleton Ship does not have summoning sickness.
  - Geralf's Messenger does not have any +1/+1 counters.
[END OF COMBO PREREQUISITES]
assistant