Talk:River Person/@comment-1731414-20190429120715

"Tra la la. Beware of the man who came from the other world."

This is neither referencing Gaster, nor So Sorry. It's a reference to Sans, who is heavily hinted to had came directly from the world of Deltarune.

This isn't something I'm just making up on the spot; hints include the song "He's Raining Somewhere Else" (Which has a melody that describes Sans as literally being within a reality he does not belong in), the fact that his room door (and the prank he pulls on 'ya) happen to correspond with the teleportation doors within the Darkner realm of Deltarune and the what one experiences before going in, respectively, and the fact that the photo of the three people only ever appears after one has talken to the Clam Girl (a character that mentions Suzie, a protagonist from Deltarune, by name).

It actually makes sense for the River Person to reference Sans, seeing as though he's the strongest monster within the Underground, causing scares even to Flowey.