Imagine a world where Jesse Pinkman was killed off in the first season of Breaking Bad. Or one where Jack Shephard died at the end of the pilot of Lost. Or one where Topanga Lawrence slowly faded away, like so many other characters on Boy Meets World.
It's horrifying to even think about, but all of these worlds could have been possible. So many of our favorite (and sometimes not-so-favorite) characters started out as minor guest stars, and it was only through the power of popularity and the magic of casting that these are now some household names. Some characters ended up lasting many years and even a spinoff or two, when originally they weren't supposed to last more than a few episodes. Would Topanga have had a real name if the writers had known she'd still be around, 21 years later?
Click through our gallery for a few of the best, most shocking and just plain upsetting TV characters who stuck around much longer than intended, including some recent fan faves like Once Upon a Time's Captain Hook and an Orphan Black clone!