A while back, I too was looking for a good horror movie. In my search, I found one that said it was about genetically altered cows killing people. Now, this wasn't what I was looking for, but I thought, "My god, if I can't laugh at something like this that probably has horns or something duct taped to a cow as it moos across the country side, I can't laugh at anything."
So I got it and was extremely disappointed. The movie I'd gotten because it sounded like a hilariously bad horror film turned out to be an excellently paced story about genetic experimentation gone wrong more akin to Alien than any horror film I've seen in quite some time.
That movie is called Isolation, and I love it.
This is the first time I've seen the trailer actually. Note the complete lack of mentioning cows?