Valkyrie's Call, Amoeboid Changeling, Spawning Pit, and Giant-Sized Flying Ant

Prerequisites

• Valkyrie's Call on the battlefield
• Amoeboid Changeling on the battlefield
• Spawning Pit on the battlefield
• Giant-Sized Flying Ant on the battlefield

Steps

1. Activate Amoeboid Changeling's second ability by tapping it, removing all creature types from Giant-Sized Flying Ant
2. Activate Spawning Pit by sacrificing Giant-Sized Flying Ant
3. When Giant-Sized Flying Ant dies, Valkyrie's Call triggers, returning Giant-Sized Flying Ant from your graveyard to the battlefield as an Angel with flying and a +1/+1 counter on it
4. When Giant-Sized Flying Ant enters the battlefield, it triggers, untapping Amoeboid Changeling
5. Resolve the Spawning Pit ability, putting a charge counter on it
6. Repeat

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite charge counters on a permanent
• Infinite death triggers
• Infinite creature sacrifice triggers