Rengar was somehow able to just spam spells without cooldown at 5 ferocitystacks. Although not the empowered spells this was still a “bit” annoying.
So heres the matchhistory of the game: http://matchhistory.euw.leagueoflegends.com/en/#match-details/EUW1/2588491225/226432283/eog?tab=overview
and here is my aof replay:
https://aof.gg/game/1/2588491225