Infinite ETB, Infinite colorless mana, Infinite creature tokens
Activate Cayth by paying and tapping it, creating a copy of the Sparring Mummy token.
When the Sparring Mummy token enters the battlefield, it and Mana Echoes trigger.
Resolve the Sparring Mummy trigger, untapping Cayth
Resolve the Mana Echoes trigger, adding for each creature you control that shares a type with the Sparring Mummy token.
Repeat.
Component Cards
How It Works
Activate Cayth by paying and tapping it, creating a copy of the Sparring Mummy token.
When the Sparring Mummy token enters the battlefield, it and Mana Echoes trigger.
Resolve the Sparring Mummy trigger, untapping Cayth
Resolve the Mana Echoes trigger, adding for each creature you control that shares a type with the Sparring Mummy token.
Repeat.