Hay Fever Pollen Mask

The Hay Fever Pollen Mask (杉花粉口罩) is a special from the Joketsuzoku village that was created to give the unhealthy a means of self-defense by enabling them to breathe a paralysis gas at their target while keeping themselves safe from its effects. Its name uses the Chinese characters for "mask" that specifically refer to a hygenic mask and the Japanese furigana for the word "masuku", the Japanese rendition of "mask".

Manga history
After Mousse obtained the Lens of Invincibility, he used it against Ranma Saotome, forcing the latter to bow down and beg forgiveness from him three times in front of others. Ranma, whose pride had taken a huge hit and was burning for revenge, then issued a challenge to Mousse. However he decided to also use underhanded methods and borrowed several items from Cologne. Like the Lens of Invincibility, these were used by the weak to defend themselves, and Ranma picked out what he felt were the most despicable. The second of these was the Hay Fever Pollen Mask, which he used to temporarily incapacitate Mousse and beat up on him. Mousse then began to fight back normally.