Halo Fountain + Intruder Alarm + Karn, the Great Creator

Prerequisites

• Halo Fountain does not have summoning sickness.
• You control a creature that can tap to produce at least .

Steps

1. 1Activate Karn's first loyalty ability by putting a loyalty counter on it, causing Halo Fountain to become an artifact creature until end of turn.
2. 2Activate a creature you control by tapping it, adding .
3. 3Activate Halo Fountain's first ability by paying , tapping and untapping it, creating a 1/1 Citizen creature token.
4. 4When the Citizen enters the battlefield, Intruder Alarm triggers, untapping all creatures.
5. 5Repeat from step 2.

Effects

• Infinite creature ETB
• Infinite creature tokens
• Infinite mana creatures you control can produce
• Infinite untap of creatures