One darling percussion instrument?

The answer to the crossword question “One darling percussion instrument?” is ACUTETRIANGLE. This is because the word “darling” in the clue is a hint towards a term of endearment, and the phrase “one” may refer to the fact that the instrument is made up of only one triangle. Additionally, the word “acute” suggests a pointed or sharp shape, which is typical of a triangle. Therefore, the correct answer to this crossword clue is ACUTETRIANGLE – a percussion instrument consisting of a small, pointed metal triangle that is played by striking it with a metal rod.