Hell's Caretaker, Corridor Monitor, and Breaching Hippocamp

Prerequisites

• Hell's Caretaker on the battlefield
• Corridor Monitor on the battlefield
• Breaching Hippocamp in the graveyard

Steps

1. During your upkeep, activate Hell's Caretaker by sacrificing Corridor Montior, returning Breaching Hippocamp from your graveyard to the battlefield
2. Breaching Hippocamp enters the battlefield, untapping Hell's Caretaker
3. Activate Hell's Caretaker by sacrificing Breaching Hippocamp, returning Corridor Monitor from your graveyard to the battlefield
4. Corridor Monitor enters the battlefield, untapping Hell's Caretaker
5. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers