The only way my friends can get a laugh, is when the make fun of someone, mostly me!?

i have one friend named halle who always makes fun of me and other people. but its mostly me, i barely have anything on her to get back at. my other friend, brianna, laughs so hard about it which makes halle just do it more. i truthfully dont think shes jelous. she starts stuff because she thinks its funny. she always calls me ugly behind my back all of the time. and then tells me how much im her best friend and im so much prettier and tighter than brianna but then to brianna she tells her the EXACT same thing. we all have the same friends and guy friends. halle could embar me SO much and if i start something with her , she really would embar me. im to the point of crying and i dont know what to do.