Yet another visual bug(arakaali fang)

So it's the first time i play the build in months since its on standard i tried to kill eater of worlds but no i can't, as soon as he starts the phase with the balls you have to walk onto and the AoE starts chasing you, when the spiders start to get hit they get some bugg graphics around them that are 3x the size of the spider, so with 20 spiders you cant see anything, the graphics look like some kind of iridescent effects from game you can put on your character, i have no idea how you can achieve a bug like this its just impressive