So As Much Fun As it is to Get 1-shot by Rengar in less than 0.5 Seconds...
Maybe damage is a bit too high? I mean even when you react to it in time, due to how his kit works, the damage still goes off and you die after flashing/dashing or CCing him.
Before anyone starts saying "doho he was fed duuur" uh yea by 1 member of our team... so he gets to kill everyone in less than half a second dealing over 1600 damage instantaneously because 1 person on our team decided to feed him? What about all of our gold? He was 3v1ing because his fucking damage was way over the top and combined we had just as many kills and CS at least for a little while. He just negated all of my gold instantly.
IDC how fed you are, that is too fuckin fast and too much god damn damage. Half the time I would Zhonya's and it would either not go off because he would kill me too fast or he would just sit there and wait for it to run out/kill whoever was there with me then me.
We ended up winning only because of Inting Sion strat...
EDIT: Everyone missing the point, Rengar being able to do this is an issue because of how his damage works. There is 0 counterplay to this EXCEPT don't feed him or be in a 5 man premade. This is toxic gameplay, he shouldn't be able to deal over 1000 damage with a single unstoppable attack, it doesn't matter if you CC him the moment you see him he still completes the jump and the damage happens regardless of whether you flashed it or not. Plus even if you Zhonya's he just waits it out. It isn't my fault someone else on the team fed him, I can't be everywhere to stop it pre-10 minutes, so he shouldn't be able to negate all my gold in a completely uncounterable 0.26 second 1-shot.