Mister Gutsy, Nim Deathmantle, Krark-Clan Ironworks, and Good-Fortune Unicorn

Prerequisites

• Mister Gutsy on the battlefield
• Nim Deathmantle on the battlefield
• Krark-Clan Ironworks on the battlefield
• Good-Fortune Unicorn 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, and attaching Nim Deathmantle to it
6. When Mister Gutsy enters the battlefield, Good-Fortune Unicorn trigger, putting a +1/+1 counter on Mister Gutsy
7. Repeat

Results

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