I was lucky enough the other day to find (in the bargain bin) a copy of the movie Timecop to add to my "movies based on comic books collection." Or, at least, I consider myself lucky--my sig-other was horrified at the purchase; but I say, a collection's a collection, and if you exclude bad things from a collection, well then it becomes a selection, not a collection. Anyway . . .
Timecop was (according to Wikipedia) one of Jean-Claude Van Damme's most successful movies, both financially and critically. The story, which you may manage to surmise from the title, involves a law enforcement agency charged with making sure that time travellers don't go messing with the past for their own illicit purposes. As far as I'm concerned, it's not a half-bad movie, with solid special effects, old-fashioned kick-boxing action, and even a nice twist about halfway through. Like every story involving time travel, it creates headache-inducing paradoxes, but c'est la vie.
Now, the credits to the movie say that it was "Based on the Dark Horse comic book", which was the basis for my including it in my collection. A Internet search reveals only one Timecop comic, which was an adaptation of the movie. So there seems to be a chicken and the egg conundrum (perhaps time travel was involved?). It's possible that the Timecop idea appeared first inside another comic, but my guess is that Dark Horse simply pitched the concept to a studio as a property and then came out with the comic once the movie got the go-ahead. It certainly wouldn't be the first time successful movies were based off of concepts that were barely noticed in the comics world--Men in Black being a good example.
Apparently the Timecop movie spawned a short-lived t.v. series, a novel line, and even a sequel movie--I can't wait until my sig-other sees Timecop 2: The Berlin Decision in my collection!