Yuna, Grand Summoner, Ioreth of the Healing House, and Saryth, the Viper's Fang

Prerequisites

• Yuna, Grand Summoner on the battlefield
• Ioreth of the Healing House on the battlefield
• Saryth, the Viper's Fang on the battlefield

Steps

1. Activate Yuna by tapping it, adding and causing the next creature spell you cast to enter with two +1/+1 counters on it
2. Activate Saryth by paying and tapping it, untapping Ioreth
3. Activate Ioreth's second ability by tapping it, untapping Saryth and Yuna
4. Repeat an arbitrarily large number of times
5. Cast a creature spell, causing it to enter the battlefield with infinite +1/+1 counters due to Yuna

Results

• Infinite +1/+1 counters on a creature