Okay, I know what you're thinking, "Runaans is **** and you should feel like ****".

Lemme stop you right there. Let's look at Teemo's skills and the progression of the game.

His passive gives him an insane attack speed boost.
His W gives him an insane move speed boost.
His E gives him an insane damage boost.
His R keeps his enemies slowed.
After you get to late game with teamfights, you won't be able to just pick people off. Runaans gives you some teamfight presense. You will be proccing your Frozen Mallet slow, your E, BoRK passive, and Lifestealing. This item is all about getting all your on-hit effects on the enemy team. The Frozen Mallet gives your AP Carry a bonus if they are a Liandry's builder!

As Stealth Assassin Teemo, the technique is to push down your enemy's top turret. This opens up the map so you can stealth it up.
1)Push the lane. This forces the enemy to respond, unless they want to lose a tower (and by all means take the tower if the top laner/enemy team is ignoring you).
2)Invis in a place where they can't see you and are unlikely to have warded. This is often times in the middle of the lane behind your current creepwave.
3)When the enemy toplaner pushes to where you are invisible, break invis by gunblading them. This slows them by a decent chunk and ****s with their reactions. It's a MOBA/ARTS/*********S philosophy that I've always believed in- a player would always rather be stunned than slowed, even if it makes absolutely zero sense.

When you are stunned, you have this "Well, I'm ****ed anyways" attitude, and also gives them time to think through what they have to do once they are unstunned. When you are slowed, you are still clicking, trying to decide what to do. You are looking at your enemy and thinking what do I have to do? Are my teammates here to help? If I blow my flash will I still escape? (People are more likely to flash when they are slowed) It's sometimes just BETTER to slow

3)Once you gunblade them, give em the good ol 1,2, buckle mah shoe. Lay down a shroom in front of their escape path. This forces them to either take another shroom slow, or to take a longer route, which you will be able to follow them through, since your W gives godly movespeed.

NOTE: Be auto attacking at this point. Once you shroom it, blow-dart it.

4) Chase them down! The frozen mallet makes this easier because they are slowed (slowing is a common theme as stealth assassin teemo)

As the title says, this is a guide to stealth assassin teemo.
Early game, you should be playing a standard teemo game, which includes trying to get some E attacks on your enemy, as it is a free damage buff. Because of this buffed damage, your trading power is up there with Riven, Udyr, Tryndamere, and the usual top-tier toplaners.

It is absolutely imperative that you do not die toplane. If you die, you lose your aggression power until you get some help from jungle, unless you are dealing with someone who doesn't get much from a gold lead. You won't be able to fully begin your stealth killing until you get Hextech Gunblade.