Yenna, Redtooth Regent, Agatha's Soul Cauldron, Ashnod's Altar, and Corridor Monitor

Prerequisites

• Yenna, Redtooth Regent on the battlefield
• Agatha's Soul Cauldron on the battlefield
• Ashnod's Altar on the battlefield
• Corridor Monitor on the battlefield
• plus enough mana to activate the Licid's ability
• available

Steps

1. Activate Corridor Monitor using the Licid's ability by paying its activation cost, attaching Corridor Monitor to Yenna and causing Corridor Monitor to become an Aura
2. Activate Yenna by paying and tapping it, creating a token copy of Corridor Monitor
3. When the Corridor Monitor token enters, it triggers, untapping Yenna
4. Activate Ashnod's Altar by sacrificing the Corridor Monitor token, adding
5. Repeat from step 2

Results

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