Neko no Fuguri

A web-based 2001-2010 Ecchi Light Novel created by the artist Torajimaneko. The story is published in both Japanese and English, the latter of which has been missing five chapters for a couple years now, and is about a boy who receives a magical cat-ears headband that turns him into a giant. Conveniently, his city is invaded around this time by ~~a giant penguin~~ Kaiju.

He's eventually joined by another boy, whose actual name is not known as a result of chapter 7 being untranslated, but is referred to as 'black cat' in the damage assessments. These two form the primary duo until they're joined by White Rabbit. Mostly this story is about little boys destroying cities. Can be read at [1] and has varying levels of NSFW depending on whether you're viewing the main storyline or the gallery.

Tropes used in Neko no Fuguri include:

And Your Reward Is Clothes Chapters 6 comes with a surprise for Fuguri, as it happens that wearing a swimming cap while transforming gets Fuguri a completely different costume in his transformed state. Chapter 10 implies that it's actually the speedo that does it rather than the swimming cap. It doesn't actually do anything, but it looks nice.
Barbie Doll Anatomy: Despite appearances, the story takes pains to avoid Clothing Damage and the none of the main characters are seen nude, largely to avoid squicking out the audience that isn't there for the shota. Fuguri's fuguri is never seen unless you deliberately go to the gallery of fan art.
Blatant Lies The front page of the website declares the main theme as "giant boy and girl crushing the city." The only girl in the story is crossdressing. At least until the Grand Finale
Dark Magical Boy Black Cat.
Demoted to Extra: If you are not Fuguri or Black Cat, you just don't exist outside your respective chapter.
Fan Service The main characters have three kinds of outfit: a leotard, speedos, and really cute school uniforms.
Engrish Some of the chapter titles get...interesting. "Fuguri found the theme of homework" indeed. The chapters themselves however, are usually exempt from this.
Evil Counterpart Black Cat starts as this before his Heel Face Turn, and late in the series we get Fake Blue Cat/White Rabbit.
Fail O'Suckyname Not immediately obvious to English readers, and it may be part of the translation convention(his name is usually written in katakana instead of kanji), but the protagonist's parents seriously named him cat testicles.
Hero Insurance: Highlighted at the end of each chapter, where the damage done by the monster and Fuguri/Black Cat is laid out in table form. Fuguri inevitably does more short-term damage than the monster, but to be fair on the kid if the Monster of the Week had stayed around then everything would be destroyed.
I Am Not Weasel: Black Cat. In the damage reports he is always referred to as 'Black Cat.' He is very clearly a long-eared dog and yet somehow no one notices this.
Lost in Translation: The title 'Neko no Fuguri' literally means 'Cat's testicles.' However, this is not the part that is really lost in translation; what is really lost is that 'Fuguri' in Japanese can refer to 'Oo inu no fuguri'('Big Dog's Testicles'), a very pretty flower otherwise known as veronica persica, and known for having heart-shaped fruit. So in short, Fuguri is a fruit.
Magical Boy: Fuguri, of course.
No Export for You: As mentioned above, the English translation has been missing more than half its content for quite a while now...and said translation is one chapter away from revealing the second main character!
Red Baron As Fuguri's real name is cat testicles, he can't tell anyone about it while gigantic. In the damage reports however, the public refers to his superhero form as "Blue Cat." Curiously, this was changed in the English version to "Cat-eared boy". His partner is likewise dubbed "Black Cat."
Shonen Upgrade / Super Mode Subverted. Some of Torajimaneko's artwork features Fuguri firing lasers from his hands while in a completely new, darker outfit with gold highlights, but Fuguri ends the series with the same powers he had at the start.
Sixth Ranger This one is an...odd, case to say in the least. White Rabbit arrives so late in the series that she never actually does anything after her Heel Face Turn because the series ends after that.
Sugar Apocalypse If Fuguri does anything while big, thousands will die. The city grows progressively more destroyed in each illustration and Fuguri's body count for Chapter 1 alone is 388 deaths and 2,951 injuries.
Too Dumb to Live Fuguri. When he needs to do research for a homework project and does it on floods, he gets the absolutely brilliant idea to cause a city-destroying flood by breaking down the dam.
When All You Have Is a Hammer Fuguri has exactly one superpower: being big. This means getting...creative, with how he fights monsters.