Hi, and Welcome to my Skarner Guide. In the build, I will show you how to use Skarner In-Lane(I'd recommend Solo Lane). Please, if you see any errors in this guide, please let me know, this is my first guide. ^-^
Anyways! On to the build (Runes/Pros & Cons)! Dun dun dun!

Pros:
Can easily stick to a enemy champ until the enemy champ is Saved or Murdered.
Ultimate is useful for bringing in a kill to your Allies
Amazing Speed/Shield with W
Model looks hawt
AoE heal
Amazing Ganker with Red and Ultimate
And..... He's amazing Overall!

Cons:
Sometimes targeted when becoming a

Huge

threat.
Not so good in a 2v2 early game (Unless jungle/Amazing lane partner!)
Expensive build :(
He steps on his cousins all the time

Greater Mark of Alacrity: I pick these runes just so when I'm chasing a enemy with Infinite slows.... my Passive takes affect with my runes and he'll never escape >;D

Greater Glyph of Alacrity: I choose those to give a little more Omph! to my AS.

Greater Seal of Resilience: I mostly use this to have a little more Armor since (I think) Skarner has like 20 base Armor points.

Greater Quintessence of Potency: Like I said, nothing's wrong with AP, especially since this is a AP/AS guide. Plus, it will give more damage to your Q -->

That's it for the runes! On to the build!

As you can see the Mastery Tree, It's not mine(Mostly 'cause I don't know how to do that), but I went 13 on Offense and 17 on Utility. I did this because the CDR on Offense and the AS plus the Spell Penetration is very nice. And on utility, The Regen of HP and MP, Exp gain, Increase durations on Buffs, and MS ect. is ALL very nice. I use these runes skill sets to catch up to an enemy and stay with him and get as much auto attacks as I can. Or maybe some Major MS with W and Trin and Lich and so on, will definitely be able to drag a champ to your team.

If you're having lots of trouble with AD or AP champs, don't be afraid to remove items to counter their sorry ***es. LikeOr. Or any others like Banshees or GA, but those are my favorites.:) You can also add likefor "NO ESCAPE" Slow lol unless they use Teleport and you don't have ult xD. So remember, don't be afraid to change items for Specific champions!

Exhaust: Amazing spell! Not only does it Slow enemies, but it also lowers their damage by 70%!!! This has Saved and Got me kills left and right, it beautiful. there's no reason NOT to get this spell. For me, I think it's a

MUST!

Flash: Wow, this spell is really OP. It's a fantastic spell. I usually use this to reach a enemy that's super fast (Yi for Ex). I press my W, Flash in to reach, quickly ult him, and then drag to Team, for the kill! And sometimes to escape :3

Ghost: This spell is

Decent,

but with all the speed we have, I don't think we'll need it, it's a good choice, but I like/ Prefer Exhaust and Flash. I'm not hating on it, but, you know. :\

Clarity: Ok, Skarner is a little mana thirsty but late game, that won't be a prob, and Clarity WILL be useless by then, so I suggest to Not get that spell, but if you like to go all out at start, be my guest.

Farming for That guysucks early game 'cause of mana problems, but he's an amazing Farmer if he has mana, so usually just sit back and relax until you get your sheen to spam some spells. His spells are we at first unlike Annie >.> (Hate that OP insane little girl) but he will D-E-M-O-L-I-S-H her late game. I can assure you of that, so just last hit, and you'll be fine.

Ok, for teamwork, you Intiate by dragging a victim to your team, that will give you the Advantage(Make sure not to drag a tank like Amumu xD). Once you received a kill, they will most likely run away, and that's when you'recomes into play, and this is the fun part too ;D. This will end up in a chasing spree, but you will most likely get another, and you WILL have a chance to push turret. This will give you the Advantage on winning. Keep spammingand.

Remember, Chase, Drag, win. is the Combo :3 always drag people to your team, have Map Awareness and listen to your team, except the bad comments! xD. Remember to Intiate because you have a shield and speed, to dodge Heavy CC like Stuns and all that. Remember, this is my first guide, thumbs are appreciated and Comments too, I would like to hear you guys and Upgrade my build. thank you all for taking you time to read my Build, thank you all! And become Amazing Skarners in the Fields of Justice!