Workhorse, Nim Deathmantle, and Ashnod's Altar

Prerequisites

• Workhorse on the battlefield
• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• Nim Deathmantle attached to Workhorse

Steps

1. Activate Workhorse by removing four +1/+1 counters, adding
2. Activate Ashnod's Altar by sacrificing Workhorse, adding
3. Workhorse dies, triggering Nim Deathmantle, causing you to pay to return Workhorse from your graveyard to the battlefield, and attach Nim Deathmantle to it
4. Workhorse enters the battlefield with four +1/+1 counters on it
5. Repeat

Results

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