Trial Chambers Boss Room? Stretch the gameplay of the chambers a bit more?

Pretty sure this idea has been suggested, but I have some alternative ideas that could be somewhat cool. Could there be an arena located somewhere in the chambers and in the center there is a weird looking trial spawner. The spawner could start to break, almost fall apart, and unleashed a boss that crawls its way out of the spawner, surely granting the player(s) a challenge. It could possibly get more difficult the more players there are. Lets say it could spawn entities like breezes or the melee mob that the chamber is assigned with. The boss could be something that fits with the trial chamber and could have some correlation with the Breeze. I feel like this could add a much more fit to the chambers because most players just leave as soon as they get what they want from it. So adding a boss could stretch out the gameplay players could have with it. Just an idea.