10 Rules To Survive A Horror Movie
6. Become A Humourless Buzzkill
Don't crack jokes. Don't be the funny guy. And certainly don't get any ideas about being the original prankster.
The comic relief never makes it to the end, and even if they do, they condemn the world around them to certain ruin a la Marty from The Cabin in the Woods. If you've got a comedy streak running through you, then your death will come all the more swiftly, even more so if you think playing a 'harmless prank' on your pals will result in anything other than vengeful haunting and just... vengeance in general, to be honest.
Being the funny character just means you're a sidekick to the protagonist, and are even more likely to die as a result of not being the main focus in your own story. Horror movies might be low hanging fruit for popping a joke here and there, but trust me, taking this deadly seriously is paramount to survival.