This is my try at AP Skarner. This will be my first published build so be nice. Also as Skarner is a pretty new champion this build can only flourish with the help of others. Before you down/up vote please give me some feedback so that I can improve this build.

+ Great lane phase
+ Can harass quite decently
+ Nice shield and healing
+ Spell spamming without much mana waste
+ Great chaser

- Losses jungle
- Lowered damage output on Shattered Earth
- Get's KS'd quite easily, having not many real "killing" moves
- Somewhat vulnerable to CC

Skarner's Shattered Earth does have some high damage output, but when you compare it to other champs with a single AD ability ( Gangplank's Parrrley or Ezreal's Mystic Shot) it really pales in comparison. First of all it scales at 80% AD, not the 1:1 ratio that champions like the ones I listed do. Even worse it only scales of bonus AD, bleh. Furthermore it doesn't do any on hit effects. AD sounds worse and worse as get going doesn't it? "But what about his passive?" you might say. Skarner is tied for first for AD - him and Cho'Gath both have 130 base AD at level 18 - so all that is needed is a bit of attack speed to really benefit from that, since his Seismic Bastion gives his 50% attack speed. Maybe with further buffs AD may become more viable.

"But what about hybrid?" you also may say. Well again you can't utilize his base AD on Shattered Earth, plus you will be sacrificing power on your shield and heal, which are keys to his survivability and maintaining a high attack and movement speed. That being said, some AD doesn't hurt at all, in fact the beginning of my build will mainly deal physical damage. What it really comes down to preference.

Energize This is what makes Skarner such a great spell spammer.

The main skill on AD or hybrid, but we are not building either. The slow on this makes it a one point wonder so we get one point it early and then max it last. Quick tip, spam this spell, it's cheap and the slow can only activate if a unit was hit earlier with it. Don't wait for a team fight to start using this, you may not be able to hit that champ a second time.

This skill gives attack speed, movement speed, and survivability. Three great things to have. Great for tower pushing, initiating and getting around map. Be careful though as the speed bonuses are lost when the shield depletes. Late game the shield will a be a nice size and you can pretty much always have this on with the help of Energize.

The main attack skill for AP Skarner. We max this first. Hit's harder than AD at early levels due to a high base damage. Plus the heal is fantastic. Makes for great laning potential. Combo this move with Shattered Earth on a minion wave for a really nice snack. This is what you will mostly use to farm, as it's relatively safe poke.

Oh boy, does it ever feel good to drag around a helpless champ with this baby. Drag 'em into a tower (making sure to slow with Shattered Earth) for almost guaranteed death. In team fights this skill will probably not get you any kills, the damage on it is not that high for an ult and only half of it gets applied at the beginning. I find that other players will take the kill before you will have the chance to, unless you can utilize his other spells properly. This spell is best use in team fights to grab those slippery bastards that can get in kill half the team, then get out (i.e. Tryndamere, Shaco and etc). The suppression from Impale cannot be canceled by crowd control, but he can't drag his target if he is stunned or suppressed. You can use your spell while this is active, so make sure you get Shattered Earth's slow ready.

Greater Mark of Attack Speed and Greater Mark of Magic Penetration are pretty interchangeable in my opinion. Find out which combo you like best, you may even choose to throw out one of them altogether. I find with my masteries and Seismic Bastion I only need a little extra attack speed early game. Another viable option is Greater Mark of Ability Power.

Yellows are really up to you, I am fan of Greater Seal of Evasion, but Greater Seal of Armor really help out quite a ton. I've been flipping between the two as of late.

I am an absolute fan-boy for Greater Glyph of Cooldown Reduction. I find though with energize, CDR is not as necessary as it is on other AP spell spammers. Greater Glyph of Scaling Magic Resist are fantastic on him, I find myself switching to them often.

Now you may be asking yourself why I choose Greater Quintessence of Movement Speed. Simply put this high movement speed makes chasing MUCH easier. Also it allows for riskier uses of Impale. With your Seismic Bastion maxed be prepared to zoom to where you are needed. Combo with Ghost for awesome. Greater Quintessence of Health are not bad either.

I won't go into much detail for these. Basically 9/21/0 (typical defensive caster) is so you can actaully live throughout fights. Make sure to grab Strength of Spirit to really gain a nice secondary bonus off of Archangel's Staff. You can sacrifice the survivability and go 9/0/21 or 0/9/21. I really don't recommend it though.

Good for escaping and chasing. Grabbing the nasty little bugger with your ult and running away. NOTE: you cannot flash while Impale is active, be sure use it before you ult or not at all.

Zooooooooooooooom! More help with ulting, and great synergy with Seismic Bastion. Chase that escaping champ and make them wish they never crossed paths with you, or run away giggling as they try to catch you.

Other Options

Combo with Flash for great survivability in fights. Can really help you pull off those hard Impale pulls.

A little more killing power. Can help when going up against healing hoes.

A guaranteed slow. Let's you and your allies chase down almost anyone. Great for 1v1 as it lowers attack speed as well.

Can be useful. I find that with his high movement speed it's unnecessary though. I'd swap it with Ghost, but that's just me.

Everything else I find not as useful on Skarner.

Core Items

Start with either Meki Pendant or Sapphire Crystal and two Health Potions. Build a Tear of the Goddess as early as you possibly can, if not wait to get it with Boots.

You can grab a gold item right before buying sheen ( kage's lucky pick or philosopher's stone), I personally don't find a need for it.

You may opt out of doing this but I find that after my boots are built I would like a little more survivability, so I grab the defensive parts to my later items. This really can be done whenever, but trust me, you will notice the difference early to mid game.

Archangel's Staff allows for you to spam skills like a boss without a worry. Wait till about 800 mana to upgrade your Tear of the Goddess. Don't try to catch every single Lich Bane proc, you are first and foremost a spell spammer, just allow a hit or two every once in a while.

Boot Choices

Early magic resist and some defense against that nasty CC. My usual choice. I am testing out the other tenacity items since they all got buffed, so this may change.

Enemy stacking Magic Resist? Grab these. I'd strongly suggest that you sell them and grab Mercury's Treads late game. That 20 flat magic pen won't help as much later on when people start getting more magic resist, that 35 tenacity will always help.

If you went with Greater Seal of Evasion for runes, these will really help against AD heavy teams. If you didn't take the runes probably better going with something else.

If nothing else seems to be needed, get these. If you took Cleanse these are an even better option.

Not my personal choice, as you are AP. Some may find them useful though.

After Core Items

The items I have listed in the build are what I usually go for, but I find there are more choices. Suggestions are welcome.

Really the only attack speed item you need. I can tear through towers and enemies alike with just this and Seismic Bastion.

More pricey than Guinsoo's Rageblade but gives some nice CDR and flat AP (doesn't build over time). I would suggest getting Stinger first, and maybe get some other items before finishing into this.

Games don't usually last long enough for to build this into anything, but I find along with your defensive skills you can be deceptively survivable with it. Remove this if you need to be more tanky.

A great option on Skarner, makes his auto attacks more powerful and allows for healing off them. Plus the slow gives you even more chasing power if you can't hit with Crystal Slash size.

I find that Skarner works well with aruas, being an all up in your grillz champ. Something else to build off of Hextech Revolver.

A great defensive and offensive team buff item that will really help out. This is what I usually swap Hextech Revolver out for.

Gives some health, armor and a nice passive that makes you all snugly warm for your enemies.

For characters that have those annoying; "Oh snap! There goes my life." spells . Like Karthus's Requiem or Caitlyn's Ace in the Hole.

So after hours of writing I hope you may be able to learn and teach me about Skarner and writing guides. Thanks to those who took the time to read this. :D