The premise: a middle school is isolated from reality, all that's outside the school grounds are creepy sand dunes as far as the eye can see. The stress brings out the worst in the student's caretakers. Lunch ladies grind children up for food, a math teacher stalks and kills students like an animal, children wander into the sandy void driven mad by fear. The main character is trying to keep his classmates safe while dealing with an hysterical mob, betrayal within his own ranks, and other grades viciously competing for resources and control. "Lord of the Flies" and "Battle Royal" are kind of similar but this has the added horror of trusted caretakers turning on their charges.
The art, while not elaborate,(I misremembered this, the art is, in fact, great. Take a look at page 128 in the big hardcover and be amazed. Edit 10/11/21) does a great job of communicating the horror through facial expressions ala Junji Ito. And, there's plenty of creative violence and shock value. Ito has a book called "The Dissolving Classroom," which I haven't read, but assume its an homage (my assumption was wrong. Edit 10/11/21).
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PS-I misremembered this comic pretty grievously but it’s worth reading