The Tenth Doctor, Reality Strobe, Agatha of the Vile Cauldron, and Birgi, God of Storytelling // Harnfel, Horn of Bounty

Prerequisites

• The Tenth Doctor on the battlefield
• Reality Strobe in exile
• Agatha of the Vile Cauldron on the battlefield
• Birgi, God of Storytelling // Harnfel, Horn of Bounty on the battlefield
• available

Steps

1. Cast the noncreature permanent by paying
2. Activate The Tenth Doctor by paying at most , removing three time counters from Reality Strobe
3. Reality Strobe triggers, causing you to cast it from exile without paying its mana cost
4. Birgi triggers, adding
5. Resolve Reality Strobe, returning Mana Vault from the battlefield to your hand, and then exiling Reality Strobe with three time counters on it
6. Repeat

Results

• Infinite storm count
• Infinite magecraft triggers
• Infinite red mana