Thornbite Staff, Ashnod's Altar, and Pestered Wellguard

Prerequisites

• Thornbite Staff on the battlefield
• Ashnod's Altar on the battlefield
• Pestered Wellguard on the battlefield
• available

Steps

1. Activate Pestered Wellguard using the ability granted to it by Thornbite Staff by paying and tapping it
2. Pestered Wellguard triggers, creating a creature token
3. Resolve the Pestered Wellguard ability from step 1, dealing 1 damage to any target
4. Activate Ashnod's Altar by sacrificing the creature token
5. When the creature token dies, Pestered Wellguard triggers, untapping Pestered Wellguard
6. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite damage
• Infinite death triggers
• Infinite sacrifice triggers