伝染るんです。

Utsurun Desu.

This manga is deemed to be one of the works that initiated the "irrational" or "unreasonable" gag comic genre where the reason of its funniness cannot be explained by logic and traditional sense of humor, which made this title very popular among teens and early twenties at that time. One of the most popular characters that appeared in Uturun Desu was "the otter", Kawauso-kun. Utsurun Desu. roughly means "it infects you" and also is the synonym for a disposable camera produced by Fujifilm (where it means "it can take photos"). (Source: Wikipedia)