Isochron Scepter + Roar of the Kha + Toymaker

Isochron Scepter

Roar of the Kha

Toymaker

How it works

1. Activate Toymaker's first ability by paying 1, tapping it and discarding a card, causing Isochron Scepter to become an artifact creature until end of turn.
2. Activate creatures you control by tapping those, adding 3.
3. Activate Isochron Scepter by paying 2 and tapping it, casting a copy of Roar of the Kha without paying its mana cost, untapping all creatures.
4. Repeat from step 2.