Putrid Goblin, Skirk Prospector, and Railway Brawler

Prerequisites

• Putrid Goblin on the battlefield
• Skirk Prospector on the battlefield
• Railway Brawler on the battlefield

Steps

1. Activate Skirk Prospector by sacrificing Putrid Goblin, adding
2. When Putrid Goblin dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. When Putrid Goblin enters the battlefield, Railway Brawler triggers, putting a +1/+1 counter on Putrid Goblin
4. Repeat

Results

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