does anybody know how to kill Mysterio in a very easy way?

relax, mysterio does take time
when he is throwing the rocks cling to side of buildings using them as cover,stay out of his range or if you are feeling lucky try to dodge the rocks and give him a smack while he is busy calling a rock
side rolls are effective here

next when he enters his machine and starts throwing missiles use similar strategies but remember -these babies track!!

shoot the guns and while he repairs climb up and give him some shots SOME,coz he won't be stunned for long

then run back shoot the other gun and so on till you get to shoot the main forcefield and then he is all yours