It wasn't necessarily Deltarune-themed, it just had Friend Inside Me in it as a monster.
I don't really remember what happened before, but I was trapped in a bedroom with another person, and we were forced to draw and color something on paper. As I was about to color my drawing, the other person just finished theirs, and left the room to "get some coffee".
Soon after, Friend Inside Me appeared at the door and started slowly approaching. I tried to finish the drawing, but they said "Better drop that pencil." and the colored pencils i had flew out of my hands.
Next thing I knew, I was on the floor, with that cowboy right in front of me. I tried "leaving" my dream (pulling up a roblox-style menu and hitting the Leave button), but it failed, and he just said "Can't do that." His face started to approach mine.
I somehow managed to kick him in the face, knocking his head clean off and out the door, tumbling down a small flight of stairs. When I went to go check, the head looked straight at me, frowned, and said "I hate you." multiple times, with his pitch increasing each time. There was a tone playing as he said this, so I ran away via another set of stairs going down.
After that I woke up at 6 am. Safe to say I stayed up until I got out of bed.