Allowing a specific player to control a custom rigged model as their character?

If a visual helps at all this is the model I've rigged: https://i.gyazo.com/thumb/1200/_917c0776fc6e125b398a879b84165b3f-gif.gif

The model was rigged and animated using plugins.

I was wondering what exactly is the best way to implement this. The player has to be able to switch back and forth between the model and a regular robloxian on demand during resets. My plan is that the player is going to have a gui that is only visible to them, so they can toggle a bool value that will allow them to spawn as the custom rigged model... But the only way I've found to make use of it so far is by setting it to the staterplayer; I don't want to make every player in this game change. I've tried looking elsewhere but I've found little on it, any help would be very much appreciated.