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
This literally goes on and on and on