Amoeboid Changeling, Avatar of Woe, and Faces of the Past

Prerequisites

• Amoeboid Changeling on the battlefield
• Avatar of Woe on the battlefield
• Faces of the Past on the battlefield
• Amoeboid Changeling and Avatar of Woe do not have summoning sickness

Steps

1. Activate Amoeboid Changeling's first ability by tapping it, giving Avatar of Woe all creature types until end of turn
2. Activate Avatar of Woe by tapping it, destroying target creature
3. When the creature dies, Faces of the Past triggers, untapping Avatar of Woe, Amoeboid Changeling and any other creatures that shared a creature type with it
4. Repeat from step 2 as desired
5. You may repeat this loop whenever a creature enters the battlefield under an opponent's control
6. You may also target another creature using Amoeboid Changeling after the first activation each turn to untap them when Faces of the Past's ability resolves

Results

• Destroy all creatures opponents control
• Destroy all creatures that enter the battlefield under an opponent's control