Board Thread:General Discussion/@comment-27274909-20160216221139/@comment-1031724-20160219005829

Bill isn't part of Stan's memory, he was just in it when it was erased. Plus Stan finished him off while he was in the middle of being erased so if he was trying some incantation that would revive him in the future, maybe Stan interrupted it.

Or maybe it's just there to make fun of how people speculate that the villain will return even after they're dead. Prime example being King Sombra in My Little Pony: He is shattered to pieces by the Crystal Heart, but a shot of his horn flying by the screen made people think he could regenerate from it, until the episode's writer confirmed his death, much to everyone's disappointment even though they hated him. At least with Bill we don't have to worry about not seeing him in later episodes, because, you know, there are no later episodes, this is series finale. It's like how the deaths of the fan-favorites in Joss Whedon series don't hurt as much as in Supernatural or 24 because he always waits until series finale to do that.

Also A X O L O T L is the code for the cipher thing, which I don't really get how all that works...