Rootha, Mercurial Artist, Hellkite Courser, Ashnod's Altar, and Heat Shimmer

Prerequisites

• Rootha, Mercurial Artist on the battlefield
• Hellkite Courser on the battlefield
• Ashnod's Altar on the battlefield
• Heat Shimmer in hand
• available

Steps

1. Cast Heat Shimmer by paying , targeting Hellkite Courser
2. Holding priority, activate Rootha by paying and returning it to your hand, targeting Heat Shimmer
3. Choose to have Rootha returned to the command zone instead of your hand
4. Resolve the Rootha ability, copying Heat Shimmer, targeting Hellkite Courser
5. Resolve the copy of Heat Shimmer, creating a token copy of Hellkite Courser with haste
6. Hellkite Courser enters the battlefield, putting Rootha from the command zone onto the battlefield
7. Activate Ashnod's Altar by sacrificing the Hellkite Courser token, adding
8. Repeat from step 2

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite magecraft triggers
• Infinite sacrifice triggers