obbodacious
A person who thinks they're the best at everything and yells about it like they're winning a championship.
My cousin is obbodacious. He yells at the TV during every game like he's the ref.
She thinks she's a rockstar because she can sing in the shower. She's obbodacious.
He bragged about his pet goldfish like it won the Olympics. Obbodacious much?