The extra stuff just before the credits I was like WTH?

Suddenly there are hot chicks topless around the pool with some guys and then they turn into zombies and one guy ends up kicking ass. I was like wth is this? LOL! I thought when I saw the chicks topless we were going to be getting a porn by mistake. There was no audio either when people were talking a little. I thought someone had included something that was not to be in this movie. LOL