Amiudake

The Amiudake is a lethal species of mushroom that grows in the Sakura Kingdom (originally Drum Kingdom). Anyone who ingests the fungus will die an hour after consumption. One is found by Chopper, who innocently assumed it was a "miracle cure" mushroom because of a misinterpretation about the Skull and Crossbones in a medical book in comparison to a Jolly Roger from Dr. Hiluluk, to cure his fatal disease. Dr. Hiluluk, after eating a soup made out of the mushroom in his loving gratitude for his surrogate son, chose to commit assisted suicide after finding out which mushroom it was, rather than letting the poisonous mushroom Chopper gave him finish him off. It made its debut in a flashback in Chapter 143 and Episode 86.