this is a lesson in not telling your friends too much about you till you know them better. Better to keep people at arms' length for a year or 3, than let them in and then have to find a way to push them back out. Especially if they infest your friends as well.

Talk to your other friends. Make sure you get your side of the story to the one or two main other friends that you have, so that they are 'innoculated' against slime-boy's counterplay. He will spin his version to these people; you need to send out the truth first.

you're down but you are not out. Think tonight about who you would need to talk to, so that he is ousted from the group and not you. And text them tonight. Talk to them, tell them your side of the story.

I say be careful what you say. He's already saying things. If you go and say things too, you're putting your friends in the position of having to choose between the two of you. People love to gossip and they love to hear gossip. Don't plead with anyone to take your side. It makes you look guilty of something. If you're a good person, let it stand with that. If he is as bad as you say, other people have noticed as well. You might lose a few friends and you might not. You don't get to choose who everyone hangs out with. Just because you no longer like this person doesn't mean everyone else is going to abandon him. Be a good person, not a backstabber. Your reputation will precede you. Sorry for your pain. We've all been through it.

If you think he's a snake in the grass, don't say anything that can be twisted. Smile and pretend to be friends and say nowt to nobody.

But if you feel there are things that he has done that you can describe and show what is wrong with them, then talk in confidence to one or 2 of your best friends about them. Don't be personal about him, ie no penis size, nose picking, smelly feet stuff. Just limit yourself to the things he's done to you that you feel are not okay.