Lab Rats + Mana Echoes + Phyrexian Altar

Mana needed: {4}{B}

BR identity

Commander legal

The 3 combo pieces

What must be in place

You control at least three Rats.

How to execute it

  1. Cast Lab Rats with buyback by paying {4}{B}, creating a 1/1 Rat creature token and returning Lab Rats to your hand.
  2. When the Rat enters the battlefield, Mana Echoes trigger, adding {C} for each Rat you control.
  3. Activate Phyrexian Altar by sacrificing the Rat, adding {B}.
  4. Repeat.
  5. If you control four or more Rats as the combo begins, this combo nets infinite colorless mana.

What the combo produces