Murderous Redcap, and Cayth, Famed Mechanist

Prerequisites

• Murderous Redcap in hand
• Cayth, Famed Mechanist on the battlefield
• available

Steps

1. Cast Murderous Redcap by paying
2. When Murderous Redcap enters the battlefield, it and Cayth trigger
3. Resolve the Cayth trigger, putting a +1/+1 counter on Murderous Redcap
4. Resolve the Murderous Redcap trigger, dealing an amount of damage to itself equal to its power
5. Murderous Redcap dies as a state-based action due to having 0 toughness
6. Murderous Redcap's persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
7. Repeat from step 2

Results

• Infinite LTB
• Infinite ETB
• Infinite death triggers