Myrkul, Lord of Bones + Ondu Spiritdancer + Grim Guardian

Prerequisites

• You have a way to kill Ondu Spiritdancer.

Steps

1. 1Kill Ondu Spiritdancer.
2. 2Myrkul triggers, creating a token copy of Ondu Spiritdancer that is an enchantment.
3. 3When the token Ondu Spiridancer enters the battlefield, it and Grim Guardian trigger.
4. 4Resolve the Grim Guardian trigger, causing each opponent to lose 1 life.
5. 5Resolve the Ondu Spiritdancer trigger, creating a token copy of itself.
6. 6Repeat from step 3.

Effects

• Infinite copies of a specific creature
• Infinite lifeloss