This Boy Suffers from Crystallization

Kono Danshi, Sekika ni Nayandemasu.

The story revolves around high school boy Ayumu Banri, who has an illness that makes him start to turn to stone when he's stressed. Since he couldn't fit in with his class, after repeating a year, he declared that he wanted to have a "Sparkly youth" as well. To do this, he changed his hair and clothes to be more fashionable, and constantly checked for popular topics to stay in ...