Welcome Blitzcrank fans! This is my first-ever guide and I'd love to hear feedback from all of you once you give this a chance. This guide is meant to deviate from the normal support Blitzcrank to (in my opinion) help players realize his full potential as a high damage, high defense offtank with the power to ruin an enemy's life with one button. If you're reading this guide chances you are thinking like this cat:
With a long range pull that will throw off any team's rhythm and a knockup that will most likely be the last thing any unfortunate adc caught in its wrath will see, Blitzcrank is probably one of the best champions for his role, which is to initiate on/assassinate squishies. He has very good cc and a spammable knockup that can be used multiple times before a fight is over, wasting the enemy's precious time as they get fisted by you and your team.

While you may be thinking "Hold on Smokey, you're trying to tell me that a support that has been nerfed time and time again is capable of doing more than just pulling things?" And I would just give you a warm hug while whispering in your ear "There there child, your life up until now has been a lie". It's normal to be afraid of the unusual, but I noticed immediately after picking up top-lane Blitzcrank that there is one major factor that directly influences your ability with him: fear. Blitzcrank feels no fear, and neither should you. Now that that's out of the way, let us begin.Does this look like the face of mercy to you?

Pros
-Good CC
-High base damage
-With cdr, can have Overdrive up almost all the time
- Mana Barrier makes the enemy cry
-Can easily interrupt channels (3 of 4 skills do this)
-Initiates very easily with Rocket Grab
-Low cd ult
-Destroys towers quickly with Power Fist

Cons
-Autoattacks feel very clunky (His E included)
-High mana costs early
-Can be tricky to trade as in laning phase
- Rocket Grab can be used improperly to help the enemy instead if not careful
- Mana Barrier can be almost nonexistent early/mid game if not careful with mana budget

Possibly Blitzcrank's weakest area, laning phase is something everyone has to go through, so you need to master it. The best summary of how to play him in lane? Play like the biggest b*tch you can imagine.

Last hitting is what Blitz usually suffers with. Any half-decent enemy laner will not let a melee champ like Blitz farm without consequences. The answer to this is to take him/her up on that offer and fight back. Early game Blitz needs to be very aggressive to take the farm he so desperately needs. This is the reason I suggested taking E at level 1, so that you can assert your dominance before going for farm in the next few levels. Example: You are up against Riven, a very aggressive laner that operates based on her cooldowns. While she doesn't have much at level 1, she can still force early trades with her Broken Wings (which she undoubtedly started with). You can expect her to immediately attack you as soon as you go for a last hit, so what do you do now since there is no escaping that at this level? You fight her back like the fearless bot that you are. Your Power Fist does twice your AD in damage, with a knockup included. This allows you to quickly pop the enemy into the air with a punch that out damages any other single autoattack, and then run away. In the case of Riven, you can't escape, so you may as well throw a Power Fist at her since she doesn't have Valor yet and make her think twice about trying that again. This is also why you start full sustain, so that you can match her harass every time. If she keeps trying every time her skills are up, eventually she will have lower hp than you, and this is when you can farm more safely.

I used Riven as the example because she demonstrates what is required of a good Blitzcrank to counterplay: cooldowns. Waiting until the enemy has no skills up (or at least not the ones they need to outdamage you/escape you) and then striking hard is how you win lane. If the enemy gained too much distance after blowing his/her cooldowns or you missed your grab, take this chance to farm up while the enemy has to stay away until skills are up again. You will take damage, that is a guarantee in basically every matchup, but that's what the sustain item start is for.

Also as another thing to think about, always watch for opportunities to grab the foe into your tower for the quickest way to assert lane dominance. This may force a Flash, which will make the enemy more hesitant to engage on you in the future.

For laning items, Tear of the Goddess on first back is a must to ensure that you can duke it out as often as possible without having to worry as much about mana problems. It also adds a hefty amount to your Mana Barrier, helping with all-ins and for escaping. Make sure to charge it by using Power Fist to last hit. Next I like to get a Sheen if I am winning, or Glacial Shroud if I am not able to land my Power Fist as often as I'd like to (and if the enemy is AD, this helps so much more). If the enemy deals mostly magic damage, I tend to forego building magic resist until later, unless I desperately need it, in which case I get an early Spectre's Cowl. Because in order to play Blitzcrank properly, you need to instill fear into the hearts of your enemies, and not play like a coward. Also, build Manamune as early as possible.

Another little bit of advice, since Blitzcrank tends to have a hard time landing his Power Fist on mobile enemies even when he grabs them first, use Overdrive beforehand so that your autoattack animation for Power Fist will be significantly quicker. Using Static Field as soon as you land your grab also prevents the enemy from flashing or using any dash skills for a bit to give you more time to land that Power Fist.

Some more advice for landing skills, if you have trouble landing your Rocket Grab for the extra burst damage, try Power Fisting them first to immobilize them for a second, take a few steps back, and then grab them right before the knockup ends for a guaranteed hit. For even more fun/range, instead of walking, you can use Flash to cover even more distance (trust me when I say this will take anyone by surprise). This is great for when the enemy is close to your tower and you want to make sure they get pulled under it, or just for ensuring that you get the damage from your Rocket Grab.

Overall, do not be afraid and trade intelligently.

This is explained in the notes for the skill section, but as previously mentioned Blitzcrank doesn't have just one skill order. I have tried many sequences, just do what you like best.

Your job during team efforts is to grab someone who doesn't want to be close to you and force a fight. Your secondary task once the fight has started is to either assassinate the squishies or to peel for yours. Blitzcrank easily separates the enemy from your carries by walking some distance away from them and then pulling the enemy to you. You can also just Power Fist them if that's all that is needed. Basically, your entire job consists of taking the enemies out of position, and then proceeding to smash their faces with your insane burst and sustained damage with Trinity Force, Muramana, and Essence Reaver. Just make sure you don't accidentally put an enemy right where they want to be, like grabbing an Amumu or Leona right into the middle of your team.
If you are in laning phase and your jungler is ganking for you (which he should, since Blitzcrank is extremely easy to gank for), it's easy to bait the enemy into attacking you. I've noticed that just going for last hits makes something click in the enemy where they cannot let you do that, and thus they attack. Use this as bait to draw your enemy closer. If this doesn't work, you can try this little trick where you position yourself so that there is a weak minion between you and the enemy, ult, then quickly grab the enemy before they realize they are in danger. It's better if you can also hit the enemy with your Static Field while doing this for more damage.

As an initiator, you have one of two options for starting a fight. One would be the obvious, Rocket Grab an enemy. The second is something I see only the more experienced Blitzcranks do, which is to use Overdrive and just walk up to an enemy to directly Power Fist them. This not only naturally scares the enemy away from cs, it also ensures you don't miss the subsequent grab right after you Power Fist the enemy. Of course, do not try this if the enemy can easily kite you and leave you with low hp. And if you miss your Rocket Grab, do not worry. Just run back to the safety of your team and wait for the cooldown before trying again. Don't be afraid to look like this guy:

Sometimes your team is perfectly capable of defending without you, which will allow you time to splitpush. Since Blitzcrank's Power Fist works on towers, it is easy to see his tower wrecking potential. If this is what you expect to do often, be sure to invest in wards so that you can get a small headstart when the enemy comes to stop you. Wards save lives, and they only cost half a minion wave each.

When claiming dragon or baron, you will want to help your team take them as often as possible. Coordinate with your team so you know when they will try for it. I say all this because there is a common scenario every time one team goes for dragon or baron and the other team has it warded (and isn't reduced to less than 4 players). The team that is trying to steal it usually waits around the outskirts of the area, throwing wards in and waiting for the chance to jump in and steal it. As Blitzcrank, this is like hanging a cookie in front of your face. Find the opportunity to grab one of them and end his/her life instantly. This will offset the rest of the enemy team and make them think twice about sticking around to steal the objective. Seriously, this is like the easiest thing to do. They wanna join the dragon raid party so badly? Let em have it.

Here is a list of items I would even consider buying:

Manamune-For obvious reasons. Actually, a better question would be why would you NOT get this?

Trinity Force-We use every stat it gives, and because +150% fisting power means a total of +9407% fisting power (estimate)

Essence Reaver-Because mana uses mana but now also gives mana and mana is love, mana is life. But in all seriousness, this item will keep you at reasonable levels of mana for both your Muramana and Mana Barrier to draw from. And the high AD and cdr needs no mention.

Rod of Ages-Even though this is an AD-centric build, Blitzcrank has 1.0 scaling on both his Rocket Grab and Static Field. Once this item is at max stacks, that is 160 more magic damage to your combo, not to mention a huge amount of hp and mana (which will also add 13 AD due to Manamune's passive, and it will cause Muramana's active toggle to deal even more). I recommend building this if you are put in more of a tanky role. I tend to get this when I need another hp/mana (because mana is basically the same to Blitzcrank item.

Iceborn Gauntlet-Although I don't build this often, I would recommend building against a high AD team (or a team where only the physical damage dealers are bothering you). Blitzcrank doesn't usually have a problem keeping up with people, so the slow field is more for your team. But just imagine an electrified icy spiked fist jammed into the rear end of your opponent. Yeah. This is why I wake up in the morning.

Frozen Heart-This item is a must-have on Blitzcrank. It gives all the armor he will ever need, half of the cdr cap, lots of mana, and a passive that will make enemies want to be around you even less. Don't worry though, Blitzcrank has a way with the ladies that keeps them always coming back (which usually involves Rocket Grab). I don't think I would ever not buy this item, since even if the enemy has no AD, Blitzcrank still uses armor for tower-diving.

Banshee's Veil-While this item does not give mana anymore, it still gives a heft amount of hp and magic resist, with a bubble that will strike even more fear into your enemies' hearts. With this item, you can even more easily start fights by Overdrive running into them and Power Fisting. It's also good defensively during sieges, since the enemy will be trying to catch you off guard with some cc and take you out of the fight. This will foil their futile efforts. Ironically, this item is also Blitzcrank's worst nightmare, so get an ally to pop it for you.

Mercury's Treads-I prefer these boots over all else. Sometimes cc isn't your biggest problem though, so choosing another option may be best then.

Guardian Angel-Since you are in the thick of the fight most of the time, this might be necessary. Try not to build too many items that give no mana, since you scale with it too well. I mostly see this as a replacement for Banshee's Veil. But it is pretty funny to see the enemy basically kill you three times over for the actual kill.

Maw of Malmortius-This item is more of an extreme case. I would only buy it if the enemy team has too much magic resist for our balanced build to handle. The passive goes very well with Blitzcrank, since his Mana Barrier will always activate and hold him at 20% hp until the shield is broken, which makes Maw of Malmortius give an extra 40 AD for the time being. The item itself also grants a magic shield on top of your shield, shieldception.

Locket of the Iron Solari-This item is useful when you have become the "support" unwillingly. When I say unwillingly I mean that you either failed top lane and are now behind on damage and/or tankiness, or your team does not need your damage to win the game anymore. Both cases make Blitzcrank very sad, but the hp, cdr, magic resist aura and shield active makes up for his poorly programmed feelings just a little bit.

Feel free to try any other items you can think of, I'm always open to new ideas!

So there you have it, now you have the fundamentals for playing top-lane AD offtank Blitzcrank. I'm not going to lie to you and tell you that you will win every game, land every grab, kill all the Teemo's, end world hunger, or beat Dark Souls without dying once after reading my guide. The message I was trying to convey is that sometimes you need to try new things to forge a new meta. This is not to say that Blitzcrank is destined for top lane offtank, but he pulls it off (see what I did there), and it is way more fun than most choices. Good luck out there and while you fend off the whining babies that know nothing of the power of top-lane Blitzcrank, enjoy the freelo. And any suggestions you have for my guide in general would be appreciated! I might have missed something crucial, so just tell me in the comments!