How to kill a spider? [Please Read!!! best answerr!]?

My friends and are having a sleepover. There is a humungous spider, HUGE, super fast. We finally caught it with a cup, but now we don't know what to do because it's under the cup. If we open in the cup, it'll run away (it's super fast!) Please help we really need to kill it, we are terrified of spiders. it wont crawl up the cup so we can't like put a cap on the cup or something, please tell us how we could kill it we're terrified. Fast as possible please!! BEST ANSWER!!