oK so in The Curse of the Time Pirate's Treasure, Alex H. mentioned that although the whole story was very non canon, there was ONE important canon part. So in the story Dipper and Mabel meet a giant talking Axolotl and they ask it what it knows about Bill Cipher. And it replies in poem -
Sixty degrees that come in threes,
Watches from within birch trees.
Saw his own dimension burn,
Misses home and can't return.
Say's he's happy, he's a liar.
Blames the arson for the fire.
If he wants to shirk the blame,
He'll have to invoke my name.
One way to absolve his crime.
A different form, a different time.
This points to the fact that Bill's dimension got burned down. Or, rather, got burned by himself. ( absolve his crime + saw his own dimension burn ) It al…Read more >