Ratadrabik of Urborg, Leyline of Singularity, and Sidisi, Undead Vizier

Prerequisites

• Ratadrabik of Urborg on the battlefield
• Leyline of Singularity on the battlefield
• Sidisi, Undead Vizier in hand
• available

Steps

1. Cast Sidisi by paying its mana cost
2. When Sidisi enters, it triggers, causing you to sacrifice it
3. When Sidisi dies, it and Ratadrabik trigger
4. Resolve the Sidisi trigger, allowing you to tutor a card to your hand
5. Resolve the Ratadrabik trigger, creating a token copy of Sidisi that is a 2/2 legendary Zombie in addition to its other types
6. Repeat from step 2 using the Sidisi token instead

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite card draw
• Infinite death triggers
• Infinite creature sacrifice triggers