Cloudstone Curio, Ugin, the Ineffable, and Herald of Kozilek

Prerequisites

• Cloudstone Curio on the battlefield
• Ugin, the Ineffable on the battlefield
• Herald of Kozilek on the battlefield
• You control a nontoken creature with morph or megamorph
• You have a creature card with morph or megamorph in your hand

Steps

1. Cast the creature card with morph or megamorph from your hand for its morph cost by paying
2. Whenever the face-down creature enters the battlefield, Cloudstone Curio triggers, returning another creature with morph or megamorph to your hand from the battlefield
3. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite storm count