Twitch

"Twitch, the Plague Rat, is a ranged marksman champion who lurks in the shadows, waiting for an opportunity to skewer his opponents with a flurry of venomous bolts. With attacks coated in deadly poison and heavy follow-up burst, Twitch excels both in short skirmishes and protracted combat, and his ability to stealth at will lets him ambush unsuspecting foes and slink away from unfavorable fights, a feature he sorely needs due to his fragility and poor escape potential. In the later stages of the game, Twitch becomes a frenzied menace, rapidly shredding through entire enemy teams if left unchecked." - League of Legends Wikia