Felisa, Fang of Silverquill, Nim Deathmantle, Ashnod's Altar, and Spiteful Squad

Prerequisites

• Felisa, Fang of Silverquill on the battlefield
• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• Spiteful Squad on the battlefield
• Spiteful Squad has at least one +1/+1 counter on it

Steps

1. Activate Ashnod's Altar by sacrificing Spiteful Squad, adding
2. Spiteful Squad dies, triggering itself, Felisa and Nim Deathmantle
3. Resolve the Spiteful Squad trigger, moving its +1/+1 counters onto another creature you control
4. Resolve the Felisa trigger, creating a 2/1 Inkling creature token for each counter that was on Spiteful Squad
5. Activate Ashnod's Altar by sacrificing an Inkling, adding
6. Resolve the Nim Deathmantle trigger from step 2, causing you to pay to return Spiteful Squad from your graveyard to the battlefield, and attach Nim Deathmantle to it
7. Repeat

Results

• Infinite +1/+1 counters
• Infinite colorless mana
• Infinite creature tokens
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers