Ratadrabik of Urborg, Leyline of Singularity, and Repository Skaab

Prerequisites

• Ratadrabik of Urborg on the battlefield
• Leyline of Singularity on the battlefield
• Repository Skaab in hand
• available

Steps

1. Cast Repository Skaab by paying its mana cost
2. When Repository Skaab enters, its exploit ability triggers, causing you to sacrifice it
3. When Repository Skaab exploits itself, its last ability and Ratadrabik trigger
4. Resolve the Repository Skaab trigger, returning target instant or sorcery card from your graveyard to your hand
5. Resolve the Ratadrabik trigger, creating a token copy of Repository Skaab that is a 2/2 legendary Zombie in addition to its other types
6. Repeat from step 2 using the Repository Skaab token instead

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite death triggers
• Infinite creature sacrifice triggers
• Return all instant and sorcery cards from your graveyard to your hand