Can I watch scary movies while pregnant, I've heard it's not recommended. I'm currently 24 weeks?

Probably correct. Scary experiences by a pregnant woman & by anyone, is probably counterproductive. Pregnant mother's thoughts likely arouse physiological responses to fear & high tides of hormones not conducive to feelings of comfort and joy; for mother or child. One of the secrets of life is that our thoughts generate our reality. Seek love and avoid fear (fearful thoughts).