A Story About a Creepy Girl's Smile

I drew this comic just for practice. The chilling expressions are the best! (Source: Author's Pixiv, translated)

Kuroi-san’s always doing something alone after class. She makes sure no one bothers her, until one day a boy happens to find out what she’s up to… and next thing he knows, he’s become her accomplice?! A short oneshot about two teenagers enjoying their hobby together.