Gongjuneun Yongui Baetsoge

A dozen elite operatives form an expedition to rescue a princess swallowed whole by a colossal dragon. Yet within the beast's belly lies a living hell—a shifting, flesh-bound labyrinth crawling with grotesque, tumorous monstrosities. Trapped in claustrophobic horror, the members fall one by one to unknown terrors. Will any of them survive to the end and bring the princess back alive? (Source: Naver, translated)