Missy, Carrion Feeder, and Horde Ambusher

Prerequisites

• Missy on the battlefield
• Carrion Feeder on the battlefield
• Horde Ambusher on the battlefield
• You have at least one red card in hand

Steps

1. Activate Carrion Feeder by sacrificing Horde Ambusher
2. When Horde Ambusher dies, Missy's first ability triggers, returning Horde Ambusher from your graveyard to the battlefield face down as a 2/2 Cyberman artifact creature
3. Resolve the Carrion Feeder ability, putting a +1/+1 counter on it
4. Activate Horde Ambusher's morph ability by revealing a red card from your hand, turning it face up
5. Repeat

Results

• Infinite +1/+1 counters on Carrion Feeder
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers