whack-a-mole

Etymology
From, from the arcade game which involves quickly and repeatedly hitting the heads of mechanical moles with a mallet as they pop up from holes. The name of the arcade game was in 1977 when it was first sold in the United States; the original game released in Japan in 1975 was called.

Noun

 * 1)  The practice of trying to stop problems, etc., that repeatedly occur in an apparently random manner; also, the act of dealing with such matters in a piecemeal manner without achieving a complete solution.

Translations

 * German: der Kampf gegen die Hydra