Ap Skarner is a very good pick for twisted treeline if the game is going into late game since his damage output is fairly high and is very tanky. I have personally played this a couple of times and id say the win/loss ratio is about 3 wins for every loss (3:1). This build is a very risky one as it is slow and expensive, however if you can pull it off it is very much worth the trouble.

Pros Spammable slow Very powerful late game Can solo Vilemaw

Cons has a slow build very weak lane phase can't do much until purchase of Rod of Ages

Ap Skarner's masteries can be done in the 2 ways listed below.

I take AP glyphs and quintessences for damage output; magic penetration marks have the same purpose, but more towards enemies that build Magic Resist.
I take 5 armor seals and 4 magic resist seals since i'm going bot lane until level 3 so i want to be able to handle their harass a bit better.

I max Shattered Earth first since in early game all your good for is the slow and its damage in early game will help you better with jungle farm than any other skill.
I max Ixtal's Impact second because it deals a fair bit of damage and heals you for a decent amount as well granting you some sustain. With proper utilization of this skill you can pick up a kill in a 2v1 and escape with Seismic Bastion ( I did so numerous times in 3 different games).
Your ultimate: Impale may have 50% scaling but due to its damage being dealt twice it basically has 100% scaling which makes it a very powerful spell since you can still use Shattered Earth while dragging the poor fool farther away from safety.

Boots and Amplifying Tome are good for early game fights and since people fight at the health pack area before minions spawn this will work well with Shattered Earth to dish out lots of level 1 damage and helping your team get first blood and possibly an ace thanks to the low cool down. Building Sheen first will help keep your damage on par with everyone else and will later build into Lich Bane. Rod of Ages is very essential to your build as it ensure you have enough hp to charge into their ranks and pick up some kills with your team close behind you. Rod of Ages in conjunction with Liandry's Torment will make you have around 3000 hp at max level allowing you to act as a side tank with your Seismic Bastion; Nashor's Tooth and Lich Bane increase your overall combat prowess and replace the need for ad on Skarner. Wooglet's Witchcap helps you further as a side tank and increases your damage quite a bit as well as allowing you to dodge lethal moves with its stasis active. If you build your items in the order listed above you can fight Vilemaw by yourself with little to no difficulty once you have built Nashor's Tooth. This build is designed to make Skarner primarily a DPS melee mage and a tank as a secondary role.

Optional Items: Rylai's Crystal Scepter to more slow to Crystal Slash or add a slow to Fracture. another optional item is Moonflair Spellblade to increase your damage, Armor/Magic Resist, and add some tenacity.

Skarner is best played as a jungler on your team you can do it 1 of 2 ways.
You can stay in bot lane until level 3 then go to jungle or you can take smite and go straight to the jungle, but the first option is recommended.
if you're staying in bot lane until level 3 then you should get wolves first when you start jungling, then if a lane needs a gank then you should do so, if not then proceed to golems and then wraiths. You should start a gank by using Seismic Bastion right before you enter the enemies vision range and charge in with Shattered Earth charged so that you can move in fast and slow the enemy down. When using Ixtal's Impact in a gank you should only use it if the enemy does not have a form of escape like Aatrox's jump in, if they do save it for when they use it as it is your only ranged move or if they decide to stand and fight you.

If you are starting with smite you should start off at golems since they are the hardest to tackle down and then move on to wraiths, after that proceed to wolves. you should not gank until you get level 3 so you can utilize your entire skill set. Always make sure that your altar is under your control when jungling.

If you are laning then you should try not to push too hard with Shattered Earth as you will not only empty your mana pool, but also make yourself vulnerable to ganks; Against an enemy with lots of harass your only option to stay in lane are properly timed Seismic Bastion and healing from Ixtal's Impact's mark. Since you can push so easily you want to focus on last hitting minions and saving your mana if possible.

When in team fights you will be expected to initiate most of the time so it is best to catch the enemies by surprise and grab the guy who does the most damage with your Impale, once that is done proceed to drag them to your allies while spamming Shattered Earth; If a Blitzcrank or a Thresh pulls them in you can also Impale then to keep them from flashing away. Don't try to solo 2 or more people because odds are is that they'll stun lock you or kite you, always keep an ally close by in case things go the wrong way.

Kayle 10/10
Kayle's early game is IMMENSELY powerful making it almost impossible to farm due to her massive damage she can deal early on from a range. against such an opponent it is best to turret hug and hope for the best as you try to farm.

Fizz 9/10
Fizz's early game is more lethal than Kayle's, but requires him to get into range so it is a bit easier to turret hug against him than it is with Kayle; It is still very difficult to lane since if you go just slightly too far then you will likely die and feed him.

Vi 7/10
Vi's early game zoning makes her a very hard champion to deal with as she can use her Relentless Force to harass you and once you get low enough she can use Vault Breaker to close in and finish the kill. Her Denting Blows is highly dangerous to you since you're squishy enough without the armor reduction it applies on you.

Ashe 8/10
Ashe's kite makes it almost impossible for you to do anything as she can either stop you from closing in on her or zone you so you can't farm.

There are other laners that i haven't posted here so if you notice them please don't down vote as i have simply forgotten them and will add them on if you tell me. I obviously won't post all of them so this area of the build is under construction until i have 5 of the most common bot laners posted here.

I would like to give thanks to summoner PRSkittles for helping me test and develop this build.

Since this build is new and still under construction this area is empty but i plan to put screenshots of successful game scores in this section. I will take screenshots from anybody, but as with all of my builds, i will only accept 9 score cards.