In Persona 5, dungeons are referred to as Palaces, the inner psyche of a person, but more specifically the arc villains, nothing in the OP implied that it was a throwaway joke.Yeah, you're right. I wrongly assumed this would be a recurrent scenario where a homeroom teacher would play jokes during the weekdays in the game. And yes, what you mention in brackets makes absolute sense as well, this would've definitely been coupled with that infamous homophobic scene if it were something similar to what I assumed.