Yoshihiro Togashi's Hunter x Hunter has some of the strongest character designs in anime and manga, and it's notable because it also has one of the most distinguishable transformations.
Gon's super powered transformation in the series is so recognizable, in fact, that a cosplay of it has gone viral in Japan after suddenly being spotted in the streets during a news piece.
やっぱあれリアルやと邪魔なんかな？?October 29, 2018
As noted by @SmSS3101 on Twitter, a wild Gon cosplayer was spotted walking around Shibuya during a special news report in Japan and the results are certainly entertaining. Not only does the cosplay catch attention for the wild design alone, as transformed Gon's super tall hairstyle has become the subject of both adulation and ridicule, but the cosplayer is just as buff as he's supposed to be.
The cosplay doesn't get too much attention from the report itself (which you can see at around 5:25 in the video above) because much of the people around him are dressed up for the incoming Halloween holiday, but it certainly left an impression among fans. The transformed, muscular Gon is one of the most popular cosplays in the entire series, and it's hard not to see why given just how eye-popping the ridiculous design is in real life.
But the transformation is portrayed in the series as anything but. It happens at one of the darkest moments of the entire series as Gon completely loses himself to rage (which had only gotten worse after watching Neferpitou save the life of someone else). This transformation leaves his body in such a tattered state, it's actually quite a while after until fans see Gon happy and healthy in the series again.
Hunter x Hunter was originally created by Yoshihiro Togashi for Shueisha's Weekly Shonen Jump magazine in 1998. The story follows a young boy named Gon Freecss, who discovers that his previously thought to be dead father is in fact alive. Not only is he alive, he is a famous Hunter, a professional traveler who specializes in finding rare treasures, exploring unidentified lands, and hunting down dangerous individuals. Gon then decides that in order to meet his father he has to become a licensed Hunter, but in that journey gets wrapped up in way more strangeness than he ever could have anticipated.