What Words do you use to get mystery gift on FireRed?

You can't get a "mystery gift" in Pokemon FireRed in the traditional sense. The game doesn't have a feature where you can receive random items or Pokemon via a specific code or phrase.

However, there are some ways to get special items or Pokemon:

* Trading: You can trade with other players using a link cable or the Nintendo Wi-Fi Connection (if your game is compatible).

* Events: Nintendo occasionally held events where players could get special Pokemon or items. These events typically required connecting to the internet.

* GameShark/Action Replay: These devices can be used to cheat and obtain items or Pokemon that are normally not available in the game.

If you are looking for a specific Pokemon or item, it's best to check online resources or forums dedicated to Pokemon FireRed for information on how to obtain it.