Heartless Hidetsugu, Gideon's Sacrifice, and Collective Inferno

Prerequisites

• Heartless Hidetsugu on the battlefield
• Gideon's Sacrifice in hand
• Collective Inferno on the battlefield
• available

Steps

1. Cast Gideon's Sacrifice by paying
2. Activate Heartless Hidetsugu by tapping it, dealing damage to each opponent equal to half their life total, rounded down, times 2, and dealing no damage to you due to Gideon's Sacrifice

Results

• Near-infinite damage