Aggretsuko: We Wish You a Metal Christmas: Red panda Retsuko, worked to the bone, unleashes her frustration in the form of death metal. Lately, though, she's found another joy—getting the most likes possible on her Instagram posts. In fact, it is said that social media attention can release endorphins. As Christmas falls upon the city, Retsuko's hunger for validation only grows, pushing her to find new ways to embellish and sugarcoat her otherwise drab life for the internet to see.