How the witch was molded

 Trevor was hungry in the middle of the night.  He gets out of bed and walks to the cupboard in the dark.  He opens up a bag full of green fuzzy bagels, eats half of one, puts the other half on the table and goes back to sleep.  In the morning he is snoring and moaning and screaming in his sleep.  I get up and see this half eaten green fuzzy bagel on table.  I wake him up and ask him where the other half of this bagel is and he says "I ate it, why? Why do you want to know?" and I say "You ate it?! It's covered in green fuzzy mold!"  To which he replies something along the lines of "oops" or "oh well" and then twenty or so minutes later after obvioulsy been thinking about this awhile he says something along the lines of "ya know people from the witch trials were eating moldy bread, maybe that's why I was screaming in my sleep...."

Wikipedia of Medical explanations of bewitchment:

A widely-known theory about the cause of the reported bewitchment attributes the cause to the ingestion of bread that had been infected by a fungus commonly known as ergot. This fungus contains chemicals similar to those used in the synthetic psychedelic drug LSD. Convulsive ergotism causes a variety of symptoms, including nervous dysfunction. 

Great.