You can go to the school authority and can complaint that they are forcing you to watch a movie and then the school will take some action to help you. nd Have a nice day
Ok this is easy there are 2 options for you to choose i am giving them below

1. I understand that being laughed at your friends does not feel that nice so you can just call them and say you have been struck with fever. with that you can skip the movie and you won't be laughed at.

2. Really looking forward to going to the movie without getting a scolding its easy as pie. tell your parents on the phone that you have extra work to do at school and will be coming late. your parents will think you are working in school, but you are watching a movie. and if they ask you what work you were doing you can say study work or teachers asked me to stay for some work