Horde of Notions, Jegantha, the Wellspring, Intruder Alarm, and Altar of Dementia

Prerequisites

• Horde of Notions on the battlefield
• Jegantha, the Wellspring on the battlefield
• Intruder Alarm on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Altar of Dementia by sacrificing any other nontoken Elemental creature, causing target player to mill cards equal to the sacrificed creature's power
2. Activate Jegantha by tapping it, adding that can't be spent to pay generic mana costs
3. Activate Horde of Notions by paying , casting any Elemental creature from your graveyard without paying its mana cost
4. The Elemental enters the battlefield, triggering Intruder Alarm, untapping all creatures
5. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana creatures you control can produce
• Infinite mill
• Infinite sacrifice triggers
• Infinite self-mill
• Infinite storm count
• Infinite untap of all creatures