Academy Researchers, Fool's Demise, and Phantom Train

Prerequisites

• Academy Researchers on the battlefield
• Fool's Demise on the battlefield
• Phantom Train on the battlefield

Steps

1. Activate Phantom Train by sacrificing Academy Researchers When Academy Researchers dies, Fool's Demise first and second abilities trigger
2. Resolve the second Fool's Demise trigger, returning it from your graveyard to your hand
3. Resolve the first Fool's Demise trigger, returning Academy Researchers from your graveyard to the battlefield
4. When Academy Researchers enters, it triggers, putting Fool's Demise onto the battlefield from your hand attached to Academy Researchers
5. Resolve the Phantom Train ability
6. Repeat

Results

• Infinite +1/+1 counters on a creature
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers