Byeong-ui Mat, Flavor's Bottle

Not having any friends is bad enough, but being swallowed by mysterious black sludge in the middle of class? The worst. Yijun is no stranger to solitude, until a school project plants the seed for a delicate bond with another loner, Suni. But friendship is a frustrating puzzle for those who are used to being alone, especially when one of them claims to control a black goo that only turns hostile when the host is gripped by anxiety. Will Yijun and Suni be able to open up and make something of their budding friendship? (Source: LINE Webtoon)