how can i meet this guy in undertale?

how can i meet this man in undertale

We are under attack!

Successful landing

#screenshotsaturday

Heya there! I really wanted to show you all a little gameplay preview of the first boss fight i'm currently working on i hope you like it ^^

Updated the chest in the maze, adding sound, particles and better animation. But what's in the chest?

Just a Pico sprite

Heya! I wanted to show some gameplay progress i made so far. I hope you like it ^^

Family band complete!

What you all think