Pentavus, Cauldron of Souls, Clock of Omens, and Ashnod's Altar

Prerequisites

• Pentavus on the battlefield
• Cauldron of Souls on the battlefield
• Clock of Omens on the battlefield
• Ashnod's Altar on the battlefield
• Pentavus does not have a -1/-1 counter on it

Steps

1. Activate Cauldron of Souls by tapping it, giving Pentavus persist until end of turn
2. Activate Ashnod's Altar by sacrificing Pentavus, adding
3. When Pentavus dies, its persist ability triggers, returning it from your graveyard to the battlefield with four +1/+1 counters on it
4. Activate Pentavus' first ability twice by paying and removing two +1/+1 counters from it, creating two 1/1 Pentavite artifact creature tokens
5. Activate Clock of Omens by tapping Pentavus and a Pentavite, untapping Cauldron of Souls
6. Repeat
7. Once you have infinite colorless mana and Pentavite tokens, you may use Pentavus' second ability to put infinite +1/+1 counters on it

Results

• Infinite +1/+1 counters on Pentavus
• Infinite colorless mana
• Infinite creature tokens
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana artifacts you control can produce
• Infinite sacrifice triggers
• Infinite untap of artifacts you control