How can you create a combo with Mairsil, the Pretender, Sneak Attack, Grinning Ignus?
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[START OF COMBO]This combo can be formed with Mairsil, the Pretender, Sneak Attack, Grinning Ignus

Color identity: UBR
Mana cost: {R}
Steps:
  1. Activate Sneak Attack by paying {R}, putting Mairsil onto the battlefield.
  2. Activate Mairsil using artifact or creature that can produce {R} by tapping it, adding {R}.
  3. Activate Mairsil using Grinning Ignus by paying {R} and returning it to your hand, adding {C}{C}{R}.
  4. Repeat.[END OF COMBO STEPS]

Result:
  - Infinite colorless mana
  - Infinite enters the battlefield
  - Infinite leaves the battlefield[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Mairsil, the Pretender must be in your hand
  - Sneak Attack must be on the battlefield
  - Grinning Ignus must be exiled
  - Grinning Ignus exiled with a cage counter on it.
  - Any artifact or creature that can produce red mana exiled with a cage counter on it.
[END OF COMBO PREREQUISITES]
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