Lurking Roper, Elemental Mastery, and Suture Priest

Prerequisites

• Lurking Roper on the battlefield
• Elemental Mastery on the battlefield
• Suture Priest on the battlefield
• Lurking Roper does not have summoning sickness
• Elemental Mastery attached to Lurking Roper

Steps

1. Activate Lurking Roper by tapping it, creating four 1/1 Elemental creature tokens
2. When the Elementals enter the battlefield, they trigger Suture Priest's first ability four times
3. Resolve the first Suture Priest trigger, causing you to gain one life
4. Lurking Roper triggers, untapping itself
5. Repeat

Results

• Infinite creature tokens with haste
• Infinite ETB
• Infinite lifegain
• Infinite lifegain triggers