Is it illegal to write a song parody?

In general, parody and other forms of humorous or critical works are protected by the legal concept of "fair use," which allows for limited use of copyrighted materials without requiring permission from the copyright holder. However, the exact boundaries of fair use can be complex and there may be instances where a song parody could raise copyright concerns. It all depends on factors such as the amount and substantiality of the original work used, the nature of the parodied work, and whether the new work creates a distinct and transformative expression. If you are planning to create a song parody, it is always a good idea to err on the side of caution and obtain permission from the original artist or copyright holder, especially if you intend to distribute or make significant money from your work. Consult legal expertise if uncertainty surrounds fair use applies to your specific parody case.