During a TV show or book, when a character you've grown to love is inexplicably killed in the third act, usually as a quick way of evoking a great deal of emotion from the audience. Named for Joss Whedon, who literally has never produced anything in which this hasn't happened.
Penny is 'Whedoned' at the end of Dr. Horrible's Sing-Along Blog Wash is 'Whedoned' at the end of Serenity
Buffy is 'Whedoned' in the season 5 finale of Buffy the Vampire Slayer
A tendency to parrot the speech patterns of various Joss Whedon characters and incorporate the slang from various Whedonverses (Buffy. Firefly, Angel, etc) into every day speech.
Every time I use the word "shiny" people look at me strangely--as though they never spoken to someone suffering from Whedonitis.
The one true b!x. The man. The myth. The curiously strong swimmer. Created Buffy, Angel, and Firefly, plus a ton of comics. The lord and master of all true TV geeks.