Jason became the scape goat for cheating on the exam, even though he was one of many who had the answer sheet.
This expression is based on a genetic defect that has now been purposely bred into some goats that we now call fainting goats. The ones today are collectible pets for people who enjoy seeing them fall over when they are frightened. The genetic defect is in their fight or flight gene, which causes them to stiffen when they need to run. But shepherds and farmers, who recognized this as a defect, would keep one per herd for this purpose: When a predator like a wolf would threaten the flock, the rest would run off while the defective goat would fall over and get eaten, allowing the others a chance to Escape. Thus the Escape Goat or Scape Goat takes the fall. Thanks to Di Oakley.
Alternative: Scape goat is a Biblical reference from Leviticus 16:8-10 and refers to taking the blame for someone else; the scape goat symbolically bearing the sins of Israel and sent into the wilderness. And Aaron shall cast lots upon the two goats; one lot for the LORD, and the other lot for the scapegoat. And Aaron shall bring the goat upon which the LORD's lot fell, and offer him for a sin offering. But the goat, on which the lot fell to be the scapegoat, shall be presented alive before the LORD, to make an atonement with him, and to let him go for a scapegoat into the wilderness. Thanks to Jeff Paynter.