Cayth, Famed Mechanist, Mana Echoes, and Bounding Krasis

Prerequisites

• Cayth, Famed Mechanist on the battlefield
• Mana Echoes on the battlefield
• Bounding Krasis on the battlefield
• available

Steps

1. Activate Cayth by paying and tapping it, creating a copy of the Bounding Krasis token
2. When the Bounding Krasis token enters the battlefield, it and Mana Echoes trigger
3. Resolve the Bounding Krasis trigger, untapping Cayth Resolve the Mana Echoes trigger, adding for each creature you control that shares a type with the Bounding Krasis token
4. Repeat

Results

• Infinite ETB
• Infinite colorless mana
• Infinite creature tokens