Yes, the Sans of the funny song Megalovania. Sanscest is the
name that the fandom gave to the
ships between a Sans and another Sans from different universes/ AU'
s-Hey, i
really like to
ship Sans from Underfell x Sans from Underswap-
-Wait, isn't it Sanscest?, because they're both a Sans but from a different
universe-
-Well, Jeremy, yes it is, if saying that they're both a Sans wasn't obvious that is Sanscest