Fiendlash, Barbed Servitor, and With Great Power...

Prerequisites

• Fiendlash on the battlefield
• Barbed Servitor on the battlefield
• With Great Power
• on the battlefield

Steps

1. Deal damage to Barbed Servitor Barbed Servitor and Fiendlash trigger
2. Resolve the Barbed Servitor trigger, causing an opponent to lose life equal to the damage dealt to Barbed Servitor
3. Resolve the Fiendlash trigger, targeting you, but dealing damage to Barbed Servitor instead due to With Great Power
4. Repeat from step 2

Results

• Infinite lifeloss