There was another film about giant rabbits. "Night of the Lepus". The special effects involve people getting big fluffy stffed rabbits thrown at their throats. It wasn't made as a joke either. Stuart Whitman, Janet Leigh, Rory Calhoun and DeForest Kelley all got themselves involved in it!
There's a great scene at a drive-in movie where the rabbits are about to attack. The movie-goers have not heard of the giant-rabbit escape from the nearby laboratory (or even that the lab. has produced them) but they all obediently turn on their lights when told to by a message flashed on the screen. The message is something like: "There's a big herd of giant killer-rabbits heading this way. Would you all please turn on your lights". They all do. No questions. No funny looks at each other. I love that little bit! Joy