[New Mode] Assassin vs Champions

I feel like there should be a mode on Summoner's Rift that basically gives one player Evelynn like abilities of invisibility passives and what not. It also gives them immense power, but it's a 1v5. They have to assassinate all of the other players while the others all look for the one. If time runs out, (say 15 min) the assassin wins, or if the assassin accumulates 15 kills. But if the 5 get 5 kills or some other number, they win.