Intruder Alarm + Phyrexian Altar + Saheeli, the Sun's Brilliance

Mana needed: {U}{R}

UR identity

Commander legal

The 3 combo pieces

What must be in place

Saheeli does not have summoning sickness.
Creatures you control can tap to produce at least {U}{R}.

How to execute it

  1. Activate Saheeli by paying {U}{R} and tapping it, creating a token copy of the creature that creates one or more creature token(s) when it enters with haste.
  2. When the creature enters, it and Intruder Alarm trigger.
  3. Resolve the Intruder Alarm trigger, untapping all creatures.
  4. Resolve the creature's trigger, creating at least two creature tokens.
  5. When the creature tokens enter the battlefield, Intruder Alarm triggers twice, untapping all creatures twice.
  6. Activate Phyrexian Altar by sacrificing two creature tokens, adding {U}{R}.
  7. Repeat.
  8. Activate any number of creatures by tapping them, adding at least {U}{R}.
  9. Activate Saheeli by paying {U}{R} and tapping it, creating a token copy of another creature you control with haste.
  10. When the creature token enters the battlefield, Intruder Alarm triggers, untapping all creatures.
  11. Repeat.
  12. If creatures you control can tap to produce at least {1}{U}{R}, this combo nets infinite mana.

What the combo produces