Saheeli, the Sun's Brilliance, Mana Echoes, Deceiver Exarch, and Prismite

Prerequisites

• Saheeli, the Sun's Brilliance on the battlefield
• Mana Echoes on the battlefield
• Deceiver Exarch on the battlefield
• Prismite on the battlefield
• Saheeli does not have summoning sickness
• available, plus an additional if you control less than three creatures that share a creature type with Deceiver Exarch

Steps

1. Activate Saheeli by paying and tapping it, creating a token copy of Deceiver Exarch with haste
2. When the token Deceiver Exarch enters the battlefield, it and Mana Echoes trigger
3. Resolve the Deceiver Exarch trigger, untapping Saheeli
4. Holding priority, if you control less than four creatures that share a creature type with Deceiver Exarch, repeat steps 1 through 3 one additional time
5. Resolve all Mana Echoes triggers, adding for each creature you control that shares a creature type with Deceiver Exarch for each trigger resolved this way
6. Activate Prismite twice by paying , adding
7. Repeat

Results

• Infinite ETB
• Infinite colored mana
• Infinite colorless mana
• Infinite creature tokens with haste