Grammar Nazi

People on the internet who dislike spelling mistakes, correcting any and everyone on their grammar in a (usually) rude manner. Nobody can escape the Grammar Nazis; they're everywhere.

Person: Your so cool!
Grammar Nazi: UM, NO. IT'S "YOU'RE" NOT "YOUR" YOU DUMBASS. YOU FUCKING IDIOT GO BURN IN HELL IF YOU DON'T KNOW THE DIFFERENCE. FUCK YOU.
Person: You're such a fucking Grammar Nazi.