H2S

H2S is the chemical shorthand for hydrogen sulfide, a poison gas that surfaced on Punk Hazard. It causes severe harm to living tissue through any kind of contact and can take vapor, liquid, or gel-like states. Caesar Clown relies on its liquid form as one of the principal components in building Shinokuni.

When packed into a compressed gel, the poison moves quickly and can kill by smothering its victims whole, inflicting agonizing burns the instant it touches them. In liquid form it grows extremely volatile and ignites if set alight. Caesar pushed the gel further by feeding it the Sara Sara no Mi, Model: Axolotl, granting the mass life and awareness as the creature Smiley, which could move, strike on its own, and fling chunks of itself across distances. Coaxing Smiley to swallow a special candy bait reverts it to gas while converting the compound into the far more lethal Shinokuni.

Caesar Clown is the gas's master, having released it across Punk Hazard four years earlier in revenge for being dismissed, an act that ravaged the island's ecosystem. He later gathered and compressed the gas into Smiley, then debuted it to underworld brokers by luring the creature with giant candy bait, triggering the Shinokuni transformation that wiped out many of his own centaur followers.