What kind of bug is this? I found it in the dormitory. It always appears.

According to the photo you provided, this bug is a bug.

Bedbugs, also known as ticks, psyllids, bedbugs, flatworms and so on. It belongs to Insecta, Hemiptera and bedbug, and is a group of Hemiptera with medical importance. They are usually active at night and feed on blood, mainly living in temperate and tropical regions.

Bedbugs can secrete an unusually unpleasant liquid, hence the name. Their appearance may affect the living environment of the dormitory. If you are troubled by their existence, I suggest you take some measures to remove them.