Spark Double, River Kelpie, and Ashnod's Altar

Prerequisites

• Spark Double on the battlefield
• River Kelpie on the battlefield
• Ashnod's Altar on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Spark Double, adding
2. When Spark Double dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. As Spark Double enters the battlefield, choose to have it enter the battlefield as a copy of River Kelpie with a +1/+1 counter on it
4. When Spark Double enters the battlefield, it and River Kelpie's first abilities trigger
5. Resolve both triggers, causing you to draw two cards
6. Repeat

Results

• Infinite card draw
• Infinite draw triggers
• Near-infinite colorless mana
• Near-infinite death triggers
• Near-infinite ETB
• Near-infinite LTB
• Near-infinite sacrifice triggers