I decided to turn this Test build into a guide, so here we go.
This will be my first guide so bear with me :P
ATTENTION: STILL A WORK IN PROGRESS
(Will go through and add Spell/Rune links later)

I Build Skarner almost like Irelia, relying on abilities and Trinity proc for damage and building very tanky in order to sustain through the teamfight and cleanup afterwards.

I have included 2 builds in this guide, but they are pretty similar.

The first one is for Solo lane Top. I feel Skarner can excell in this lane due to his healing/sustain and ability to go toe to toe with someone.

The second build is for jungling as it uses Smite. This is the role Skarner was designed for and is played in the Champion Spotlight. He clears the Jungle fast and uses blue buff well as his abilities drain his mana very quickly.

Pros:
-Fast Jungler
-Good sustain in lane
-Good chasing ability
-Scales well with many different stats
-Durable if built correctly
-Good at 1v1
-Good initiator

Cons:
-Slightly lacking in damage
-Jungle ganks slightly weak
-Huge mana issues without blue buff

For runes I usually run:

Greater Mark of Desolation x9 - Standard on any Physical damage dealer. While some people may argue that Skarner does large amounts of Magic damage, when built with Trinity Force I feel his auto attacks are a large percent of his damage. Other options: Greater Mark of Attack Speed(great choice for jungle build), Greater Mark of Attack Damage

Greater Seal of Armor x9 - Helps your early laning phase substantially which will help you win your lane. These will also help you take less damage from minions when you go in for harass. Other options: Dodge, Mp5, AP


Greater Glyph of Magic Resist x9 - Again, helps your early laning phase, primarily against abilities and harassment. Staying healthy in the lane will allow you to zone out your opponent and prevent him from farming. Other options: Mp5, Flat CDR(another great choice for jungle), AP, MR/lvl

Greater Quintessence of Health x3 - These can vary based on your tastes. I personally run Flat HP because your first toe to toe fight with your enemy will usually decide who wins the lane, and 78 HP at level one is a decent amount. Flat HP is almost necessary for jungling as your fastest route will take you dangerously close to death (less than 100 hp) Other options - Movespeed, Armor Pen AD/AP,

I run 16 Defense, the rest in Utility for both builds (except for Plentiful Bounty for jungling). This setup ensures additional early HP and defensive stats as well as some Mp5 Meditation , Movespeed Quickness , Blink of an Eye , and Buff durations Utility Mastery for jungling.

Other options for Masteries include 9/21/0 0/21/9 or even 0/9/21, It is pretty much up to you as most of the stats in any of the trees are useful for Skarner.

For laning I prioritize E for the healing aspect (if you are getting fed delay the last one or 2 ranks by a level or 2 as taking them early could cause you to 1 shot the minions which wont allow you to heal off of them)

I level Q second as it increases sustained damage and slowing power allowing you to pick up kills.

I level W last (1 point at lvl 4) as the shield strength is weak and the Atk Speed/Movespeed increase for leveling it up is minimal.

Obviously take your Ult whenever possible

For jungling I level Q first causing you to clear the jungle faster and with blue buff you can spam it pretty well.

E comes next as it will give you sustain and not require you to buy additional health pots after the first 5

Lastly is W (except for 1 point at lvl 4 for ganking) for the same reasons as before.

Grab Ult whenever possible.

[ - almost a necessity due to its immense utility. Use it to catch someone off-guard, then grab the enemy with , pulling them back into your team to initiate the teamfight. Use it to escape over walls or get out of a bad positioning. Use it as a gap closer to begin your chain-slow with . There is just so much utility in this single spell that it should be taken always. Sadly, you cannont use while channeling .

Other options:

- This is the ONE other spell I would consider taking instead of flash, if flash just isn't for you.

2nd Summoner Spell:
This one is more debatable and based on your personal tastes. The 4 I would choose between would be

- If you are jungling of course.
- Great true damage and reduced heal. While not that great late game, the early game power of this ability will net you many kills if used in the right situations. This will also help in your first toe to toe fight in Top lane, possibly granting you lane dominance.
- Not as good as in my opinion as Skarner already has a permanent slow, but the range on this spell could allow you to close the gap and proc your Q.
- Skarner is a great tower defender against One or Two people due to . Pick this if your team needs someone to defend against backdoors and minion pushes. I would consider this a situational pick, as or will help you tremendously with early laning.

I will post a Laning Guide later on as I have not been able to lane against some of the more dominant solo lane champions and would only be able to provide a broad description at this point.

As a brief overview: Try to last hit and use E + Q combo to heal off as many minions as possible. If the enemy gets too agressive, when you hit 6 you can pull him into your tower for a kill. Conserve your mana. Don't waste Q's on minions (unless Q + E Combo) or E's when
you are at full HP as Skarner has serious mana issues.

Champions I have beaten in lane at this point include:
Rumble
Mordekaiser
Olaf
Nidalee
Renekton
Akali

I will continue to update this guide as best as I can. Feedback and criticism are welcomed but please have reasoning behind your suggestions rather than "this is just the way I build him."

Thanks for reading, and I hope you enjoy running people down as a predatory scorpion! :P