LSD

LSD is a drug often used by the Beatles to hallucinate. People who used it had what was called an acid trip. Some people had "good trips" where they say great things. If you were watching football on TV, they might see angels instead of players. There were also "bad trips" where people saw terrible things. If you had a bad trip while watching football, the players might be skeletons and coming at you. Many years later, someone who had LSD would have a flashback where, no matter what kind of trip they had, would see HORRIBLE things. LSD is illegal now.