Well… no one was correct

https://undertale.wiki/d/t/what-do-you-think-jackenstein-will-do-in-castle-town/1962

well...

He was part of a gag that is purely there to take a shot at Materia lol

Which was better than any of these possibilities imo

Aqua Wave * Lowkey I forgot what he said when you talked to him (just that he appears in Top Bakery)

He tried to make a spincake but then it got “copyright claimed”, and when you enter the music shop spin chef is in there

Aqua Wave * I... don't remember that. I really need to replay Chapter 5.