Colfenor, the Last Yew, Sifter of Skulls, and Ugin's Conjurant

Prerequisites

• Colfenor, the Last Yew on the battlefield
• Sifter of Skulls on the battlefield
• Ugin's Conjurant in hand

Steps

1. Cast Ugin's Conjurant by paying
2. Ugin's Conjurant enters the battlefield and dies as a state-based action due to having zero toughness
3. Colfenor and Sifter of Skulls trigger
4. Resolve the Colfenor trigger, returning nothing from your graveyard to your hand
5. Resolve the Sifter of Skulls trigger, creating a 1/1 Eldrazi Scion creature token
6. Activate the Eldrazi Scion by sacrificing it, adding
7. The Eldrazi Spawn dies, triggering Colfenor, returning Ugin's Conjurant from your graveyard to your hand
8. Repeat

Results

• Infinite +1/+1 counters on Ugin's Conjurant
• Infinite colorless mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers
• Infinite storm count