9. Now for a Theory: Smile Dip
This chapter is written by GirlOfManyFandoms.
Okay, so we all know about Smile Dip, which gave Mabel crazy hallucinations.
"The future is in the past! Onward, Aoshima!"
What if Bill Cipher created it as a way to screw with your mind?? I mean, he is a mind demon, and he has to have a little fun while he awaits in the "Netherworld" to be summoned again. He could be able to use it as a weapon. If he has this "candy" working around in your brain, he could get you to spill secrets, and you wouldn't remember anything because of the raging Smile Dip hangover you have later.
Either that, of Smile Dip is just sugar mixed with LSD...