Jumbo Cactuar, and Selvala, Heart of the Wilds

Prerequisites

• Jumbo Cactuar on the battlefield
• Selvala, Heart of the Wilds on the battlefield
• undefined available

Steps

1. Declare Jumbo Cactuar as an attacker, triggering its ability, giving it +9999/+0 until end of turn
2. Activate Selvala by paying and tapping it, adding 10,000 mana in any combination of colors

Results

• Near-infinite colored mana