dipper makes jokes about his mental illnesses to hide how messed up his brain really is

look at me i'm dipper hey guys look at me i'm crazy oh look a floating triangle haha he likes to steal souls too i'm paranoid etc

bill but his eyelashes are detached from his eye

thaT'S rIgHt iT's mE bILL cIPhEr

bill lost his memory and is trying to remind himself what his name was. suddenly, he forgot he was to take over gravity falls.

bill forgets who he is