Modrem Thrasher's insane tendrils
You’re referring to the Leeching Thrasher, I presume. The trick is to get close to it, since its tentacles can’t reach close around it for some reason. However, this becomes troublesome it there are multiple ones focusing you, which can happen.
I know about the melee range thing. What I meant was it attacks without line of sight. And I can confirm on multiple occasion, there was only 1 and not even looking at me. Not even once. It was concentrating on someone else. If it had looked at me once, I won’t say anything as it already registered by char there and can attack anytime, but I was facing to it’s back all the time and I still get hit? If this is not call OP, I don’t what is already. And people are screaming OP for condi builds now! LOL.