Agatha's Soul Cauldron, Wildwood Mentor, Phyrexian Altar, and Thopter Squadron

Prerequisites

• Agatha's Soul Cauldron on the battlefield
• Wildwood Mentor on the battlefield
• Phyrexian Altar on the battlefield
• Thopter Squadron in exile
• Wildwood Mentor has at least one +1/+1 counter on it
• available

Steps

1. Activate Wildwood Mentor using Thopter Squadron's first ability by paying and removing a +1/+1 counter from it, creating a 1/1 Thopter artifact creature token
2. When the Thopter enters the battlefield, Wildwood Mentor's first ability triggers, putting a +1/+1 counter on itself
3. Activate Phyrexian Altar by sacrificing the Thopter, adding
4. Repeat

Results

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