Lurking Roper, Elemental Mastery, and Trespasser's Curse

Prerequisites

• Lurking Roper on the battlefield
• Elemental Mastery on the battlefield
• Trespasser's Curse on the battlefield

Steps

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

Results

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