also: なりすな
noun
singing sand; whistling sand; squeaking sand
Sand that produces sound when walked on or otherwise disturbed; a natural phenomenon found on certain beaches.
この海岸の鳴き砂は、歩くとキュッキュッと音がする。
The singing sand on this beach makes a squeaking sound when you walk on it.
鳴き砂は世界的にも珍しい自然現象だ。
Singing sand is a rare natural phenomenon worldwide.
Compound of 鳴き (naki, 'crying, singing', continuative form of 鳴く) + 砂 (suna, 'sand'). The reading なりすな uses the classical attributive form 鳴る (naru).