Koll, the Forgemaster, Deathrender, and Reckless Barbarian

Prerequisites

• Koll, the Forgemaster on the battlefield
• Deathrender on the battlefield
• Reckless Barbarian on the battlefield
• Deahrender attached to Reckless Barbarian

Steps

1. Activate Reckless Barbarian by sacrificing it, adding
2. When Reckless Barbarian dies, Koll and Deathrender trigger
3. Resolve the Koll trigger, returning Reckless Barbarian from your graveyard to your hand
4. Resolve the Deathrender trigger, putting Reckless Barbarian from your hand onto the battlefield and attaching Deathrender to it
5. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite red mana
• Infinite sacrifice triggers