So, who's this champion that costs 6300 ip and why should I bother playing him?

Ever since buying him, I could not take my hands on Zac. He is hands down, the most fun champion in league to play. The enemy team couldn't hate you any more when all they're doing is getting bounced around and dying to you and your team. Zac has what I think is the greatest gank in the game, as well as an awesome engage and disengage. His kit boasts unique utility that is used to help your teams set up kills, while proving that there's more to being broken than getting kills and tallying on assists.

What makes or breaks playing Zac in a game is the positioning that you (yes you, not me), the player, puts himself into. In order to succeed, its essential that a good Zac player is good at predicting, timing, and reacting to whatever it may be around him/her. It is under your decision making that will make or break team fights, and under your continued decision making who lives and who dies. Zac's kit is rather diverse, allowing him to peel for his carries or even bounce himself to an enemy backline causing all hell to break loose. Zac is an awesome champion because he benefits any team composition. His gank, along with his soft CC should be enough to acquire an easy kill, especially if you have ult and flash.

It's not the end of the world if you miss an E, as a flash+ult can set your team up to the kills you originally intended. Zac's kit isn't the friendliest with making mistakes, as you may end up misplaying and intended kill, but it can rather be forgiving. Say an all-in isn't so much what was once intended. Zac still has his ult for a disengage (granted it wasn't burned before), as well as his flash and E as an escape, plus his passive in the time which his team may be able to turn something around.

Pros

Best Gank in the game
Easy Jungle Clear
Offers great utility in his kit
Extremely tanky champion, almost impossible to kill
One of the best passives in the game
AOE damage everywhere
You get to bounce around Summoners Rift

Cons

Teammate reliant
No spike damage
Useless when stunned, snared, rooted, etc.
Can be kited if abilities are missed

Blue Side Start

As Zac you're going to want to start at gromp. It's important that you pick up Zac's blobs between autos as it reduces the cooldown on his W by one second for every blob. This will allow for a faster and efficient jungle clear. Keeping that in mind, focus the large golem for your autos when you move to the blue camp next. you will be Q'ing all the camps minions as well as making sure your W is damaging all of them. You might have to burn a potion at this point. When finished head to wolves. Kill wolves using the same method and observe your health and mid laner. This is important because at this point you will either kill scuttle or gank mid. Remember that the range on your e is still small and that the mid-laner should be in range of your E to you so you can maximize the effectiveness of your gank. If you decided to kill scuttle you should be at full health when you're done. If you chose not to gank before you can gank either top/mid, or head to raptors to continue clearing. Always pay attention to your lanes and gank when needed. Finish by smiting Red buff and Krugs. Congratualtions, you've finished your first clear with Zac! Proceed to either a) gank b)recall c)continue to clear.

As far as being invaded goes, do not worry too much as it won't put you behind. Just continue to clear elsewhere if it is a one time occurence. If you are finding yourself being invaded often ward up and let your team know what's going on. Letting yourself being invaded often will hurt you in the long run, which hurts your team just as much.

I'm not particularly fond of invading the enemy jungle until I know that I've become an absolute monster, as you want to minimize throwing the game from being caught out. By reducing the amount of mistakes you take, the easier it is to secure your team a victory. IF you do plan in clearing enemy camps, make sure to have wards lying in their jungle so you may have ample time to react and get away.

As the best ganker in the game, you want to capitalize on any mistake the opposing team makes, especially if it's pushing lane or diving under tower. If a lane is pushed passed the middle, they've already gone too far and will probably have to burn a flash after you E over to them. Just make sure that when you're going to gank you communicate with your team using pings to let them know you're coming so that you won't be the only one stopping by to say hi to the enemy laner(s).

What's awesome about Zac is his ability to gank from any angle. If you find that when you walk up to prepare a gank in a bush or a particular area and the enemy laner backs off, the area is warded. Simply retrace your steps and try another spot. Ex) If you are ganking the mid laner from below from the bush and he backs off, you should back off and head for the lane closer to his tower. Don't make it obvious you are walking there and stay in the fog of war. Hug the wall so their mid laner is within range of your E and secure the kill. Don't be discouraged after a failed gank attempt!
You are the tank. Peel for your carries and disrupt theirs. As Zac, you should be able to disrupt and enemies backline long enough for your team to react. If you are bombarded by abilities and ultimates and you die, it's alright because at that point your team should be finishing up and have won the fight. You'll be almost impossible to kill anyway, especially with your passive, so be smart, know your surroundings, know who to focus, and make sure to communicate with your team.

For ganking I will always start with Elastic Slingshot. E in, followed by an immediate W+Q or Q+W. At this point you will have chunked any squishies and they will be panicking. Under your own judgement, don't be afraid to ult. If you do it is likely to secure a kill, but don't wait too long as you're opening up the window for them to escape.

Keep in mind that you can spam you're W as you're ulting so you can do even more damage on top of the chaos you've already caused.

I want to thank everybody who read this guide. I really appreciate your guys taking the time to read it as it's the first guide I've decided to put up on MobaFire. I look forwards to updating this guide further in the future and hopefully you enjoy bouncing around on Summoners Rift as much as I do. Thank you~!