Mox Opal + Retraction Helix + Rona, Herald of Invasion // Rona, Tolarian Obliterator

UB identity

Commander legal

The 3 combo pieces

• Mox Opal
• Retraction Helix
• Rona, Herald of Invasion // Rona, Tolarian Obliterator

What must be in place

Rona does not have summoning sickness.
You control at least three artifacts.

How to execute it

1. Activate Mox Opal by tapping it, adding {U}.
2. Cast Retraction Helix by paying {U}, targeting Rona.
3. Activate Rona by tapping it, returning Mox Opal from the battlefield to your hand.
4. Cast Mox Opal by paying {0}.
5. Rona triggers, untapping itself.
6. Activate Mox Opal by tapping it, adding one mana of any color.
7. Repeat from step 3.

What the combo produces

• Infinite colored mana
• Infinite storm count