Jumbo Cactuar, and Brightmare

Prerequisites

• Jumbo Cactuar on the battlefield
• Brightmare in hand
• undefined available

Steps

1. Declare Jumbo Cactuar as an attacker, triggering its ability, giving it +9999/+0 until end of turn
2. Cast Brightmare by paying
3. When Brightmare enters the battlefield, it triggers, causing you to gain life equal to Jumbo Cactuar's power

Results

• Near-infinite lifegain