Board Thread:General Discussion/@comment-26006155-20190617222636/@comment-26006155-20190621053456

We don’t know the circumstances that led to Sans falling (or at least, we think he fell from above. We see Chara do this, but not Frisk) into the Ruins without his costume.

Any number of thinks could have happened.

Remember that artist design universes, and build a Rube Goldberg machine to create circumstances, not to create a likely story, but to tell the brilliant improbable story they want to tell.

So if you want a character to encounter an earlier version of themselves, you create rules that make this possible.