Kiki-Jiki, Mirror Breaker, Mardu Warshrieker, and Umbral Mantle

Prerequisites

• Kiki-Jiki, Mirror Breaker on the battlefield
• Mardu Warshrieker on the battlefield
• Umbral Mantle on the battlefield
• You have attacked this turn
• Umbral Mantle attached to Kiki-Jiki

Steps

1. Activate Kiki-Jiki by tapping it, creating a token copy of Mardu Warshrieker with haste
2. When the Mardu Warshrieker token enters the battlefield, it triggers, adding
3. Activate Kiki-Jiki by paying and untapping it, giving it +2/+2 until end of turn
4. Repeat

Results

• Infinite ETB
• Infinite creature tokens with haste
• Infinitely large Kiki-Jiki until end of turn