Trazyn the Infinite, Grim Monolith, and Prismatic Geoscope

Prerequisites

• Trazyn the Infinite on the battlefield
• Grim Monolith in the graveyard
• Prismatic Geoscope in the graveyard

Steps

1. Activate Trazyn using Prismatic Geoscope's ability by tapping it, adding five mana of any color
2. Activate Trazyn using Grim Monolith's ability by paying , untapping Trazyn
3. Repeat

Results

• Infinite colored mana
• Infinite colorless mana