Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Phantom Train + Old-Growth Educator

Prerequisites

• You've gained life this turn.

Steps

1. 1Activate Phantom Train by sacrificing Old-Growth Educator.
2. 2When Old-Growth Educator dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. 3When Old-Growth Educator enters, it triggers, putting two +1/+1 counters on it.
4. 4Resolve the Phantom Train ability.
5. 5Repeat.

Effects

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