Here are some rap lyrics that could fit an underground beat: "I'm deep in the trenches, where the streets never sleep My rhymes are like a maze, that you can't escape, it's deep I'm the voice of the underground, the one you never knew My flow's like a subway train, it'll take you to the truth, boo I'm not afraid to get dirty, to get real, to get raw My words are like a sword, they'll cut through the flaws I'm the king of the underground, the one who holds the crown My rhymes are like a revolution, they'll turn the game around" Please note that these are just examples, and you can always modify them or come up with your own to fit your style and the beat. Remember, underground rap is all about being authentic and true to yourself, so don't be afraid to express yourself and show the world what you're made of!