The Jolly Balloon Man, Agatha's Soul Cauldron, Midnight Guard, and Great Whale

Prerequisites

• The Jolly Balloon Man in exile
• Agatha's Soul Cauldron on the battlefield
• Midnight Guard on the battlefield
• Great Whale on the battlefield
• Midnight Guard has at least one +1/+1 counter on it
• Midnight Guard does not have summoning sickness
• You control at least one mana-producing land

Steps

1. Activate up to seven mana-producing lands by tapping them, adding at least
2. Activate Midnight Guard using The Jolly Balloon Man's ability by paying and tapping it, creating a token copy of Great Whale that is a 1/1 Balloon with flying and haste in addition to its other types
3. When the Great Whale token enters the battlefield, it and Midnight Guard trigger
4. Resolve the Great Whale token's trigger, untapping up to seven lands
5. Resolve the Midnight Guard trigger, untapping it
6. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite creature tokens with haste
• Infinite token copies of each creature you control with haste except Midnight Guard
• Infinite mana lands you control can produce
• Infinite untap of lands you control