Originating from a 1983 video game, Spelunker ventures into treacherous caves seeking treasure, navigating hazards like falls, toxic vapors, and ghosts. He utilizes tools including a pistol, pumps, and dynamite for these expeditions.

An OVA adaptation reimagines him as a high school teacher. This version exhibits extreme physical fragility, dying instantly from minor incidents such as short falls, light impacts, rubbing his eyes too hard, or consuming shrimp tails. He resurrects moments after each demise. Environmental triggers also prove fatal, like mistaking humidifier vapor for deadly cave gases, inducing panic fueled by residual trauma from his explorations.

Psychologically, Spelunker possesses a profound fear of death, manifesting PTSD-like symptoms. This anxiety dictates daily choices, leading him to anxiously request meals that "won’t kill him" in restaurants. Despite constant deaths, he approaches teaching earnestly, delivering safety lectures grounded in his lethal experiences, though his morbid examples unsettle students and colleagues.

Character development emerges through his adaptation to school life. Initially known only for repeated deaths, later segments show periods where he avoids dying, causing others to miss his "inspiring" demises. A delinquent student initially targets him but recoils upon realizing Spelunker's vulnerability could implicate the student as a murderer. Paradoxically, Spelunker demonstrates unexpected physical resilience during confrontations, challenging assumptions about his frailty.

His personality remains stoic and emotionally detached, often underreacting to danger. This contrasts sharply with sudden outbursts of terror when facing perceived threats, amplifying the comedic effect of his predicaments.