Day 26 - Season finale that made you say, "OMG WTF?!"

There are two season finales that I've seen that are the epitome of this. One I've only seen on the Internet, as I didn't watch the show, but it deserves special mention because it involved the extinction of an entire species.

First runner-up: The season finale of Dinosaurs.

( In which the world is destroyed by a plastic fruit factory. )