As Gangplank in you one of the strongest Champions in the game because of his Parrley and his auto attack. Gangplank's auto attack is as strong as his parrley because the damage is constant,this build is for both. he does about 1k crits and his auto attack is also 1k every 2 seconds he deals 2k every two seconds while auto attacking. his auto attack is about his most dangerous attack with this build. but his parrley is not useless. gangplank's slow and poison passive with parrley could be the only reason you even getting a kill while chasing,then let the auto attack do the damage. Also good to note that you should not depend on your auto attack to kill everyone, in most cases you are set up with a range or a very annoying champion where your not able to farm this is where your parrley comes in to play, it is best used in and out of a bush and the early item Faerie Charm helps you maintain your mp up at all times with two Faerie Charm giving 3 mana every 5 seconds you will be receiving 6 mana every 5 seconds. this will help you push your enemy away from the exp range and deal the extra 7 damage from your poison passive that can stack up to 3 times.