Repercussion, Donna Noble, and With Great Power...

Prerequisites

• Repercussion on the battlefield
• Donna Noble on the battlefield
• With Great Power
• on the battlefield

Steps

1. Deal damage to Donna Noble
2. Donna Noble and Repercussion trigger
3. Resolve the Donna Noble trigger, dealing damage to an applicable target
4. Resolve the Repercussion trigger, dealing damage to Donna Noble instead of you due to With Great Power
5. Repeat from step 2

Results

• Infinite damage to target opponent