Marath, Will of the Wild, Agatha's Soul Cauldron, Wildwood Mentor, and Phyrexian Altar

Prerequisites

• Marath, Will of the Wild in exile
• Agatha's Soul Cauldron on the battlefield
• Wildwood Mentor on the battlefield
• Phyrexian Altar on the battlefield
• available

Steps

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

Results

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