Gives him unstoppable, a max hp shield, does percantage max hp damage to your opponents, gives you a sheen affect after the duration, stuns you, and increases all cc durations against you. You can't even build against the fucking thing, adaptive helm doesn't work, trust me I've tried, and the only thing that can even fight him top lane is something like Vayne top, which ruins the comp for the rest of your team. Why hasn't this been addressed? The ability is completely overtuned. God forbid you'd be able to do anything level 6 either, because his ult is damn near impossible to miss now that it's instant.
This doesn't even cover the fact that his Q slows you for like 80% of your movement speed, so getting away from him is way too challenging, and the fact that he can just buy an item in lane and theoretically never have to back, so he gets a powerspike 5 minutes before you do.