I'm thinking of calling the cops on my friend just to joke around.
Why would you do that to your friend?
It's just fun to do it. It's entertainment.
Police officers are very busy. Calling the police for fun is no laughing matter. They might arrest you instead.
Stop being such a spoil sport.
What you are doing is called swatting, and people have been killed by being swatted. Don't do it at all.