Isochron Scepter, Benefactor's Draught, and Karn, the Great Creator

Prerequisites

• Isochron Scepter on the battlefield
• Benefactor's Draught in exile
• Karn, the Great Creator on the battlefield
• You control creatures that can tap to produce at least

Steps

1. Activate Karn's first loyalty ability by putting a loyalty counter on it, causing Isochron Scepter to become an artifact creature until end of turn
2. Activate creatures you control by tapping those, adding at least
3. Activate Isochron Scepter by paying and tapping it, casting a copy of Benefactor's Draught without paying its mana cost, untapping all creatures and drawing a card
4. Repeat from step 2

Results

• Infinite card draw
• Infinite mana creatures you control can produce
• Infinite storm count