Board Thread:General Discussion/@comment-26006155-20190820122909/@comment-26006155-20190822011257

Ambassador, it's looking increasinly likely that your theory that Gaster's memory was erased from the world is real.

Hyperdeath Asriel gives us the recipie for doing that, when he says that's what he's going to do to Frisk. Kill him over and over while resetting, and each time his friends will remember him less and less.

This could very well be what Sans did to Gaster once he warped back into the past. Despite Gaster's massive impact on the monster world, nobody seems to remember him, and all of his followers seem to have warped in from another timeline.

I've left this out of the script for now, in case the two of us wanted to do a collab, or you wanted to present this theory yourself.