Gwenna, Eyes of Gaea, Cloudstone Curio, Sheltering Ancient, and Tempting Wurm

Prerequisites

• Gwenna, Eyes of Gaea on the battlefield
• Cloudstone Curio on the battlefield
• Sheltering Ancient on the battlefield
• Tempting Wurm in hand
• Gwenna does not have summoning sickness

Steps

1. Activate Gwenna by tapping it, adding that can only be spent to cast creature spells or activate abilities of creatures
2. Cast Tempting Wurm by paying
3. Gwenna triggers, putting a +1/+1 counter on it and untapping it
4. Tempting Wurm enters the battlefield, triggering itself and Cloudstone Curio
5. Resolve the Tempting Wurm trigger, allowing each opponent to put any number of artifact, enchantment, creature and/or land cards from their hand onto the battlefield
6. Resolve the Cloudstone Curio trigger, returning Sheltering Ancient from the battlefield to your hand
7. Activate Gwenna by tapping it, adding that can only be spent to cast creature spells or activate abilities of creatures
8. Cast Sheltering Ancient by paying
9. Gwenna triggers, putting a +1/+1 counter on it and untapping it
10. Sheltering Ancient enters the battlefield, triggering Cloudstone Curio, returning Tempting Wurm from the battlefield to your hand
11. Repeat

Results

• Infinite +1/+1 counters on Gwenna
• Infinite ETB
• Infinite LTB
• Infinite storm count