Madhouse's anime adaptation of ONE's One Punch Man was highly praised by fans for its incredible animation, and great translation of ONE's creation and illustrator Yusuke Murata's art.

One of the biggest moments in the first season of the anime was the Hero's Association's battle with the Sea King, and now one Madhouse animator has revealed a bit more of how it became the final product.

Twitter user @bahijd did key animation work for the anime, and released a .gif of the key animation from episode 9, where Saitama fights the Sea King. Specifically the scene depicts when Saitama finds the injured Mumen Rider, and is thusly assaulted from behind by the Sea King.

The moment is not only hilarious because of how little the Sea King's punch has an effect of Saitama, but the way Saitama's head innocuously bounces from the weak attack. Couple that with how amazing the scene is given that the rain around them quickly spreading out of range, and the impact comes through the screen.

The scene right after is an animation marvel as well when Saitama punches a hole straight through the Sea King while the rain stops across the entire city for just a brief moment.

For those unfamiliar with One Punch Man, the series follows Saitama, a regular working Joe who one day puts a stop to a violent villain attack. After this fight Saitama is inspired to become a hero. Training his body hard everyday, he's eventually granted with extreme strength. Looking for a worthy opponent, Saitama joins the Hero Association in the hopes of fighting them. But every fight he gets into ends after a single punch! Forced to wander through life increasingly bored of his supreme power, Saitama has become hilariously disconnected with the world of action around him.

One Punch Man started life as a webcomic by series creator ONE in 2009. After going viral, surpassing seven million hits in June 2012, illustrator Yusuke Murata approached ONE about redrawing the series for a release in Shuiesha's Weekly Young Jump spin-off webcomics. Thirteen volumes of the series have been released as of this date.

VIZ Media bought the rights to distribute the manga in English, and the series was later adapted into a 12 episode anime series from Madhouse. The series first aired in Japan in 2015, and later debuted its English language broadcast on Adult Swim's Toonami block in 2016. A second season of the series is currently in the works.