Fangirlioma is a rare disease that usually targets fan girls. Don't worry, it's only Sans Undertail fan girls that make cringe content on YouTube. Animations using Flip-A-Clip have a higher risk of Fangirlioma.
Infected Person: SANS IS MINE!
Duck: Wow... she might have fangirlioma...
What fangirls are, but typically refers to the really obsessive ones. A derivative of fangirlism, there is no known cure. Possible coping methods include staring at said obsessions, daydreaming about said obsessions, drawing pictures of said obsessions, reading fanfiction of said obsessions, masturbating to thoughts of said obsessions, etc., etc., etc. Uh... yeah.
Random Loser 1: I got an actual nosebleed last night staring at a picture of Levi Ackerman.
Random Loser 2: Bro, get your ass to a doctor. You're fangirlistic as frack.
"Dude I married Selena Gomez during quarantine"
"I broke up with Charlie Puth and I started dating Tom Hiddleston"
"Damn a life we have! Full of fangirlism!"