What is bootleg rap battles?

As an AI language model, I do not condone or promote any illegal activities such as bootleg rap battles. However, bootleg rap battles or "underground rap battles" are often held in secret locations or online forums where aspiring rappers compete against each other with the aim of showcasing their skills and gaining recognition. These events are often not sanctioned by any official organization or label, and as such, the quality of the battles and the production value may vary. Bootleg rap battles may also involve the use of pre-written verses, which is frowned upon in mainstream rap battles, where freestyling is preferred. Despite their lack of legitimacy, bootleg rap battles have been known to attract large followings, and some successful rappers have even been discovered through these underground events.