Underworld Breach + Lotus Petal + Brain Freeze

Prerequisites

You have at least six other cards in your graveyard, plus an additional four cards if Brain Freeze is in your graveyard.

Steps

1. Activate Lotus Petal by tapping and sacrificing it, adding {U}.
2. Cast Lotus Petal from your graveyard for its escape cost by exiling three cards besides Brain Freeze from your graveyard.
3. Repeat from step 1 one additional time.
4. Cast Brain Freeze either from your hand by paying {1}{U}, or from your graveyard for its escape cost by paying {1}{U} and exiling three cards from your graveyard.
5. Brain Freeze's storm ability triggers, creating at least two copies of Brain Freeze targeting yourself, and any remaining copies targeting an opponent.
6. Resolve each Brain Freeze, causing yourself to mill nine cards and, if applicable, an opponent to mill three cards for each Brain Freeze remaining.
7. Repeat.