Bjorna, Nightfall Alchemist, Othelm, Sigardian Outcast, Intruder Alarm, and Cathodion

Prerequisites

• Bjorna, Nightfall Alchemist on the battlefield
• Othelm, Sigardian Outcast on the battlefield
• Intruder Alarm on the battlefield
• Cathodion on the battlefield
• Bjorna and Othelm do not have summoning sickness

Steps

1. Activate Bjorna by tapping it and sacrificing Cathodion, targeting any creature
2. Cathodion dies, adding
3. Activate Othelm by paying and tapping it, returning Cathodion from your graveyard to the battlefield
4. Cathodion enters the battlefield, triggering Intruder Alarm, untapping all creatures
5. Repeat an arbitrarily large number of times
6. Resolve all Bjorna abilities, dealing infinite damage to any creature(s)

Results

• Infinite colorless mana
• Infinite damage to creatures
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana creatures you control can produce
• Infinite sacrifice triggers
• Infinite untap of all creatures