Mairsil, the Pretender, Sneak Attack, and Grinning Ignus

Prerequisites

• Mairsil, the Pretender in hand
• Sneak Attack on the battlefield
• Grinning Ignus in exile
• 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
• available

Steps

1. Activate Sneak Attack by paying , putting Mairsil onto the battlefield
2. Activate Mairsil using artifact or creature that can produce by tapping it, adding
3. Activate Mairsil using Grinning Ignus by paying and returning it to your hand, adding
4. Repeat

Results

• Infinite colorless mana
• Infinite ETB
• Infinite LTB