Athreos, Shroud-Veiled, Reluctant Role Model, and Phantom Train

Prerequisites

• Athreos, Shroud-Veiled on the battlefield
• Reluctant Role Model on the battlefield
• Phantom Train on the battlefield

Steps

1. Activate Phantom Train by sacrificing the creature with a coin counter on it
2. When the creature dies, Athreos's second ability and Reluctant Role Model's ability trigger
3. Resolve the Reluctant Role Model trigger, putting a coin counter onto itself as well as +1/+1 counters if those were present
4. Resolve the Athreos trigger, returning the creature from your graveyard to the battlefield
5. Resolve the Phantom Train ability from step 1
6. Activate Phantom Train by sacrificing Reluctant Role Model
7. When Reluctant Role Model dies, it and Athreos's second ability trigger
8. Resolve the Reluctant Role Model trigger, putting a coin counter and +1/+1 counters onto the other nontoken creature
9. Resolve the Athreos trigger, returning Reluctant Role Model from your graveyard to the battlefield
10. Resolve the Phantom Train ability from step 6
11. Repeat

Results

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