Torchling, Dual Casting, and Seething Song

Prerequisites

• Torchling on the battlefield
• Dual Casting on the battlefield
• Seething Song in hand
• available

Steps

1. Cast Seething Song by paying
2. Holding priority, activate Torchling by paying and tapping it, copying Seething Song
3. Resolve the copy of Seething Song, adding
4. Activate Torchling by paying , untapping it
5. Repeat from step 2

Results

• Infinite magecraft triggers
• Infinite red mana