Skarner, is (in my opinion) one of the best junglers in the League to date. But of course as with most champions, they work best with certain other champions. Skarner is a tanky DPS hybrid character, and should by played as such. While also maintaining versatility and flexibility. Never assume that the guide is 100% and should be followed to the T. Always build for the situation, I have tried to add in sight variations depending on the situation at hand, such as boot choice.

Thanks for reading my guide and I hope you find this helpful :)

~Drespar

Pros:
Very durable
Fast late game
Good CC with Ultimate, Crystal Slash spam, Randuins and Crystal Scepter
Amazing Ultimate that can drag carries into the open
Great ganking capabilities in tandem with champions such as morg
Good Self healing even without life steal

Cons:
EXTREMELY dependent on blue buff, almost through the entire game
Getting counter Jungled can be devastating
If not careful can be easy to kill

Runes and Masteries were chosen to both help with minion kills and augment Skarner's already tanky nature for both late game and early game ganking. Now while Seals and Glyphs are for Defense, Quints and Marks are for offense, Skarner is a tank DPS, and should, as said before, be played as such. The Runes were chosen to help with early game damage, as Skarner's damage scales quite well even without items (although still not compareable to a graves with 6 blood thirsters, so don't just forgo damage items).

Flash is usually first choice for any champion, but because of Exoskeleton ghost is almost useless. That and Flash helps close a distance quickly, or dive into the enemies to Impale the carry and drag them into the open.

Smite is usually another choice, especially for junglers. KEEP IN MIND THAT SMITE SHOULD BE USED TO GUARANTEE A DRAGON/BARON/BUFF KILL! NOT TO JUST DO A LOT OF DAMAGE EARLY ON! This is why junglers take smite! Not just to speed up jungle times, but to guarantee extra income for the TEAM. ALWAYS use Smite to secure a Dragon/Baron/buff kill, avoid using it on anything else!!!

pretty self explanatory.
Take crystal slash at level 1, because it does AoE damage and provides a slow, so it speeds up jungle times as well as makes ganks easier.
Exoskeleton should be taken at level 2, it provides a great shield for early game jungling, and provides a speed boost.
Level 3 again take a point in crystal slash for more damage,
level 4 grab fracture to stay in the jungle even longer.

After level 4 you should be maxing crystal slash first, then fracture, then exoskeleton, with impale when possible. Don't max Exoskeleton right away as the increasing movement speed increase in negligible after rank 1. Although when late game comes around, thats when max exoskeleton really shines, as you can push over 500 movement speed with exoskeleton up. This will make chasing easier, as well as closing the gap for impale a lot simpler.

The jungle route is as follows:
Leash at Blue > Wolves > Wraiths > Golems > Lizard

Popping health pots at Blue, Wolves, Wraiths, and Lizard. This should leave you with 2-3 health pots, depending on your leash. After about level 4 in jungle you won't need health pots for jungle any more because fracture will be enough to sustain your health. The remaining health pots should be used (for the most part) to restore health after attempted ganks.

Skarner is best used as a jungler. But he is best used a jungler with champions who have immobilizing effects, such as Morgana, Ryze, Lux, Annie (stun), Nautilus (Passive stun), Taric, Caitlyn, etc. If you impale the target and drag them into the open the person in the lane should be able to land their lock down and keep them out longer almost ensuring a successful gank.