little did asriel know is that "mirror" is a view into an alternate dimension

Finally someone who acknowledges that deltarune is another universe

And not a sequel

Well if MY mirror started offering me cookies, I'd be damn glad and take them if I could. The politely thank the person in the mirror.

Asriel: (in college smoking a fat blunt) *sees Ralsei also smoking a fat blunt in the mirror* I gotta stop smoking this shit.