Mister Gutsy, Nim Deathmantle, Krark-Clan Ironworks, and Thunderous Velocipede

Prerequisites

• Mister Gutsy on the battlefield
• Nim Deathmantle on the battlefield
• Krark-Clan Ironworks on the battlefield
• Thunderous Velocipede on the battlefield
• if Mister Gutsy doesn't have a +1/+1 counter on it available

Steps

1. Activate Krark-Clan Ironworks by sacrificing Mister Gutsy, adding
2. When Mister Gutsy dies, its second ability and Nim Deathmantle trigger
3. Resolve the Mister Gutsy trigger, creating a number of Junk tokens equal to the number of +1/+1 counters that were on it
4. If you created a Junk token, activate Krark-Clan Ironworks by sacrificing a Junk, adding
5. Resolve the Nim Deathmantle trigger, causing you to pay to return Mister Gutsy from your graveyard to the battlefield with a +1/+1 counter on it, and attaching Nim Deathmantle to it
6. Repeat

Results

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