Cyborg Grandpa G

We can remake him, faster, stronger, more destructive and... better at farming?

I've become a remodeled human to perform the best agriculture in Japan... no, the world. My name is the farming cyborg... Cyborg Grandpa G!

One day, Tokijirou Kaizou, a 70-year old man, decided to convert himself into a cyborg to become the greatest farmer in the world. His family is as baffled as the audience.

An early work by Takeshi Obata, one half of the Death Note duo. And probably the only reason why anyone even knows about this.

Tropes used in Cyborg Grandpa G include:

Amazingly Embarrassing Grandparent: It's class inspection day - everything's been polished, the pupils are on their best behaviour, even the teacher has cleaned up - then Kei's grandfather (guess who) smashes through the window and embeds himself in the blackboard in the shape of a G. It gets worse.
Anvilicious: Subverted mercilessly. G-chan does try to hammer what he considers to be important lessons into the heads of anyone who happens to be nearby, but his methodology is somewhat more explosion-oriented than it ought to be.
Badass Grandpa: Obviously.
Beyond the Impossible: G-chan doesn't agree with your interpretation of the word "impossible".
BFG: Subverted. Doctor Sharekoube takes impressive looking inventions and manages to make them less threatening.
Card-Carrying Villain: Sharekoube-sensei tries so very hard, though.
Calling Your Attacks: Which change just about every time, and are usually ridiculously named.
Cloudcuckoolander: "I did my research watching anime!"
Cool Shades: Just take a look at that picture up there.
Eye Beams: Just one of Tokijirou's many powers.
For Science!: Subverted. His great scientific/technological prowess is dedicated entirely to furthering agriculture... which is technically a science... right?
Gatling Good: Minigun scarecrows. Yes.
Hot-Blooded: STRONGER G!!!
Instant Armour
Instant Awesome, Just Add Mecha
Mad Scientist: The titular character turns himself into a cyborg over the course of two days... FOR AGRICULTURE!
Mecha: the tractor turns into one in an emergency... for some reason.
More Dakka: Part of Grandpa's schtick seems to be adding guns, armor and overpowered engines to anything with the structural fortitude to withstand it, including himself. The scarecrows are reminiscent of something out of Transmetropolitan, and both his farm and his new house in the city are quickly outfitted with a terrifying arsenal that could probably take down a small battalion.
New Powers as the Plot Demands: If G-chan needs to do something, he just build himself a new invention or makes a new modification to his body.
No OSHA Compliance: No one can work on Tokijirou's farm, since he forgot to disable the defense grid after he left. It wasn't even exactly safe for his family when they still lived there.
- Also, when he tries to get a part-time job, it doesn't take long for him to attempt to make "improvements" to his workplace.
Old Master: Tokirjirou can not only kick your ass, but will out-invent you any day of the week.
President Evil: The Mayor.
Refuge in Audacity: The only way G-chan gets away with most of his activities is by living in a world that seems to fear giving him any sort of retribution. Otherwise he would be in jail for all sorts of crimes.
Rule of Cool/Rule of Funny: The defining rules of this universe, since the laws of physics and the entire nation of Japan have clearly stopped working.
Stealth Pun: Grandpa calls himself "G-chan." The word "ji-chan," pronounced the same way, means "grandfather."
Stuff Blowing Up: All the time, for no apparent reason except that Grandpa thinks it's a good idea. Also 'cuz it's awesome.
Super Cyborg
Technical Pacifist: G-chan's rivalry with Sharekoube is a result of a disagreement over how cybernetics ought to be used. Sharekoube wanted it for military purposes, Tokijirou for agricultural purposes. Of course, G-chan causes way more destruction with his "non-military" inventions than Sharekoube ever does with his "weapons."
There Is No Kill Like Overkill: Grandpa's response to there being crows in his field? Blow up the field.
- Not to mention the tractor with the fighting power of an F-16.
Tim Taylor Technology
Toilet Humor: Grandpa's cyborg body runs, in part, on manure. The byproducts of this are used to... interesting effect.
What Do You Mean It's Not Awesome?: Even to the people who love it and have done it all their lives, farming is a tedious and time-consuming activity. Not when G-chan does it, though!
- It's not surprising considering this comes from the same person who gave us dramatic writing and dramatic potato chip-eating.
Xanatos Roulette: Buh... the tractor... part of the plan all along? How is that even possible?