[Have Mabel just stare at Dipper for a good long while! Sure, there's chaos and destruction all around them but to know that her brother has been here for this long and she didn't even notice?

How else was she suppose to react?]

But that's impossible! I just saw you on the bus with me! This isn't one of those weird time travel thingies is it?

Because I know what I saw! And you totally were with me!

[She was with him all this time...wasn't he...??]