Hello summoners! This is not a joke. No, Im serious. This is...*drumroll* TOPLANE TERROR THRESH!
This is a pretty new (I think) strategy/build for Thresh. He is usually played as a tanky initiator support. But he is actually very effiecient top. He counters almost all AD melee champs that go top, thanks to his range, heavy damage Basic Attacks and his free armor from his souls!
He scales well with the late game and if you are fed you will almost always win thanks to your crazy thresh snowballing powers! Read on for the full guide and hope you enjoy! :D

PROS

Ranged

Amazing Passive

Heavy Damage Early and Late

Many hard CC spells

Good in teamfights

Fun to play :D

CONS

Early Squishiness

Hard to land Q

Q: Death Sentence

This is Thresh's initiate ability. It can be hard to hit, but when you learn to hit it you will be a monster >:D. Remember to press Q a second time to drag yourself to them so you can land basic attacks and your E.

W: Dark Passage

When you play solo top this is mostly used for the shield when 1v1-ing or escaping. But you can still use it to save allies or help your jungler when they are ganking top. When doing this, thro your lantern near them and walk towards your enemy and Q or E him to you. Then your jungler should jump with the lantern to you and help you finish your victim off.

E: Flay

This ability is extremely useful. You can use it to push people back when they charge at you, or use it backwards to get them closer to you. Try to combo this with your Q and/or ult to lock your target down completely. My favourite thing to do with this spell is to fake recall near turret when I am low-life, when they come closer I Q myself to them. Barrier to block their counter attack then E them into turret and ult to make the turret hit them more.

R: The Box

This ult is good when initiating a fight with Q to make sure noone escapes your Thresh-Terror
You can also use the ult to slow enemies that are chasing you.

Start with a dorans blade, one health potion and a warding totem.
Dorans Blade help you get lifesteal to stay in lane so you can outfarm your enemy early.
The health potion is also good for sustain, and of course the warding totem so you do not get ruined by ganks.

Next you want to get your bloodthirster ASAP but it is good to buy boots if you have some money over after going B and u still can't afford BF Sword.
If you are against an AP toplaner or if they have much heavy AP or CC on their team you should go for Merc's Treads. If they have a fed ADC or if you are against an ad toplaner that relies on basic attacks (for example Tryndamere) you should go for Ninja Tabi.
Also get Frozen Mallet for the AA slow and the large amount of health.

Get Hextech Gunblade or Trinity Force in whatever order you want. It's good to get both because it will cause all of your abilities to deal more damage while still giving AD.
Hextech Gunblade gives both spellvamp and lifesteal. Both those stats will be useful when
1v1-ing and teamfighting. Trinity Force gives you Everything! If you are building towards TF first buy Phage, then Sheen and then Zeal.

Wits End is good cause your basic attacks will deal 42 bonus magic damage and steal some Magic Resist from your opponent. This is fantastic but I would suggest buying it as your last item.

Get Randuins if you need more tankiness and armor REMEMBER TO USE IT when you Q in to their team so you can lower their adc damage.

Get Maw of Malmortius if they have a heavy AP burst assassin that is fed. For example Fizz or Ahri.

Get Zhonyas if they are building incredible amounts of armor and no magic resist. Also get it if you are having trouble with a global ulter like Ziggs or Karthus.

I take 21/9/0 Because it gives thresh tons of damage and a little bit of tankiness.
"Arcane Blade" is amazing on thresh cause it causes his basic attacks to deal even more damage!

This is some tips n' tricks when playing thresh top.

REMEMBER TO LASTHIT! do not just auto attack a minion and hope you get it, only hit it when it
is at low life. You want to try to have the minion waves as close to your turret as possible while still having it out of turret range so the turret doesn't steal any minions.

Poke your opponent with Basic Attacks! Also when you have your E you can wait between autoattacks to deal sick damage with just one basic attack. When your little flay icon is red your next basic attack will deal extreme damage. Be careful while doing this cause you might miss cs while loading your basic attack.

Collect your souls! (do not overextend though) If you collect your souls you PERMANENTLY gain armor and AP! This will have a huge impact on your late game cause you will be tanky enough to survive lots of hits while still dealing almost as much damage as an ADC.

Combo your spells! (Basic-initiate-one-target-and-auto-attack-him-to-death-combo-deluxe)
(QQEWR)
Grab him with Q and drag yourself to him with Q, then E him backwards to lower his chances of escape. Use W for damage protection and R for your target to have no chance of escape. After your combo just auto attack him to death. (or flee if needed)

(Escape-combo)
(ERW)
E to knock them back, R to slow them down alot and W to block damage if they charge at you or if ezreal, jinx, or someone else with a global ult is about to ult you. Additionally if they dive you you can Q them and drag them into your tower or your team.

Thanks for reading my Toplane Terror Thresh Guide.
Feel free to leave feedback and try this Thresh playstyle out for yourselves.
Have Fun! :D