Tidespout Tyrant, and Grim Monolith

Prerequisites

• Tidespout Tyrant on the battlefield
• Grim Monolith in hand
• undefined available

Steps

1. Cast Grim Monolith by paying its mana cost
2. Tidespout Tyrant triggers, returning a nontoken permanent that can be cast using from the battlefield to your hand
3. Activate Grim Monolith by tapping it, adding
4. Cast the nontoken permanent returned in step 2 by paying its mana cost
5. Tidespout Tyrant triggers, returning Grim Monolith from the battlefield to your hand
6. Repeat

Results

• Infinite colorless mana
• Infinite storm count