How do i end friendships or make him stop.?

Well i have had this friend for like 2 years NOT really one of my best friends.I can't trust him.He always talk behinds my back to one of my best friends.My best friend tells me what he says and says he just fakes his laughs and agreeing with him when he talks behind my back but a lunch he tells me all about what he says.He winks at me to let me know his just faking his laugh and stuff.I didn't really like him on the first year i met him anyways.But back to the present.He allways says mean stuff to me and his like Ricky you don't have a sense of humor in a way like his showing off.He like almost trying to take my friend all to himsel.He says lets not be friends with me to my best friend and other stuff talking behind my back.He says lies to my best friend he said.He said i show off to my friend whitch i don't and my friend agrees with me he says im trying to be cool but all i did was play 1 soccer game?We all sit together in desk and he whispers it too my best friend right beside me.He calls me a tool EVERYDAY he sees me!He whispers to my friend then i whisper to my friend saying what did he say then he tells me then the other person is like your a tool i can hear you.I always see him whisper to my friend then i put my ear near them kinda like saying i can hear you.Then he says mind your own buisnees but i think it has alot to do with me!He always whispers to my friend something bad about me when im a good distant or not looking at him.He trys to act tough and when my best friend is gone he always talks behind my best friends back but when his hear its always me?!If i talk behind back its because they annoyed you one day but its on topic!But he just talks behind my back everyday for no reason!Im always nice but that doesn't help he says im scared of getting in trouble.When i try to say anything to him he just says your mom infront of what i said.He trys to hang out with my best friend and ditch me/avoid me? I don't even think his my friend!He does that even when i first meet him and just always does it.1 mounth ago he hanged out with me but still did the stand thing im like why do you keep talking behind my back his like Ricky get a sense of humor and always insults me.He always says i talk behind eveyones back thats not true everyone says his talking behind everyone back.Im afraid of talking to him becuase his going to say this if me and my friend tells him to stop.He will probably say your mom.Then call us a tool.Then insult me and start going around telling everyone about it to humiliate us and be mad and insult us like you guys are show offs and stuff like that or im a show off you brag exc..What should i do!?!?Thanks