Bellowing Aegisaur, Ghyrson Starn, Kelermorph, Spark Double, and Temple Altisaur

Prerequisites

• Bellowing Aegisaur on the battlefield
• Ghyrson Starn, Kelermorph on the battlefield
• Spark Double on the battlefield
• Temple Altisaur on the battlefield
• You have a way to give Bellowing Aegisaur indestructible
• You have a way to deal damage to Bellowing Aegisaur

Steps

1. Give Bellowing Aegisaur indestructible by any method
2. Deal damage to Bellowing Aegisaur, with all but 1 of that damage being prevented by Temple Altisaur
3. Bellowing Aegisaur, Ghyrson Starn, and Spark Double trigger
4. Resolve the Spark Double trigger, dealing 2 damage to any target
5. Resolve the Ghyrson Starn trigger, dealing 2 damage to Bellowing Aegisaur, with all but 1 of that damage being prevented by Temple Altisaur
6. Spark Double and Bellowing Aegisaur trigger
7. Resolve the Bellowing Aegisaur trigger, putting a +1/+1 counter on each other creature you control
8. Resolve the Spark Double trigger, dealing 2 damage to Bellowing Aegisaur, with all but 1 of that damage being prevented by Temple Altisaur
9. Ghyrson Starn and Bellowing Aegisaur trigger
10. Repeat from step 5

Results

• Infinite +1/+1 counters on all creatures you control except Bellowing Aegisaur