Chuunibyou

Chuunibyou is an internet slang term used to describe someone who believes or pretends to have special powers or abilities that are typically associated with fictional characters or anime. It originates from the Japanese word “chuunibyou,” which translates to “eighth-grade syndrome.” This term is commonly used to refer to people, usually teenagers, who display delusional behavior and have an exaggerated sense of self-importance.

Examples:

I used to have chuunibyou when I was in middle school; I thought I had magical powers and would often daydream about being a hero.
John’s chuunibyou is getting out of hand; he keeps insisting that he can control people’s minds and tries to cast spells on them.