In Need Of Some Help

Hello! Well where should I start.... Well as you can see I am currently writing a story, and as the title says, I am in need of some help.

So here's a question just to get ideas flowing: What would be the most shocking thing to ever learn of a best friend?

I need some crazy answers, not just things like, "He/she talks behind my back" or "He/she did something behind my back" No i need things BIG, things that would shock the hell out of you! Crazy things that would be almost unbelievable!
Also think of things like maybe committing sexual crimes, etc. things of that nature, all bad, and just unbelievably crazy, that you wouldn't expect from anybody really.

Tell me what you think? I'd love to hear everybody's ideas.