There's the original ending to I am Legend before it was re-shot. For those that don't understand, the entire movie was suppose to not just be "another zombie flick," but actually the inverse of the typical zombie movie. If you can't figure it out, Will Smith was the bad guy. The entire movie the creatures that had evolved or mutated from being infected with the virus had become another species with their own means of communication, compassion, love, feelings etc and the humans in the film acted with fear and panic towards change. They lashed out and attacked the "zombies" rather than seeking to understand them and this in turn lead to the violence in the film.
The entire reason the film was suppose to be called "I am Legend" was because Will Smith's character was suppose to be the creature's legendary monster. He'd experimented and killed so many of them because he didn't see them as equal to humans or see any value in their life. Only at the end could he see he was in fact the bad guy, the creatures never meant him any harm. The entire film was re-edited and some portions re-shot to ironically make the movie just like other zombie movies. What was suppose to be a demonstration of how xenophobia, fear, change, and general lack of understanding can cripple the entire world and our species turned into "DERP DERP BLOW EM UP" because they were afraid it was too intellectual for the general public.