How it works
Prerequisites
- You control at least one artifact creature token.
- Xavier Sal does not have summoning sickness.
- There is a removable counter on a permanent you control.
Steps
- 1Activate Xavier Sal by tapping it and removing a counter from a permanent you control, creating a copy of an artifact creature token you control.
- 2When the creature token enters the battlefield, Intruder Alarm and Serum Tank trigger.
- 3Resolve the Intruder Alarm trigger, untapping all creatures.
- 4Resolve the Serum Tank trigger, putting a counter on it.
- 5Repeat.
Commander brackets
In which brackets is this combo allowed, per Spellbook's Exhibition tier?