The term 'TINY, MISCHIEVOUS BEING' can be summarized by the crossword solution 'ELF' (3 letters). Elves are mythical creatures found in many cultures around the world. They are usually depicted as small, mischievous beings with magical powers. Elves are often associated with nature and are said to live in forests or underground. In some stories, they are portrayed as helpful and wise, while in others they are seen as malicious and dangerous.