Fly In Tha Carter II Lil Wayne

call me Pac-Man, your ghosts is blue

This could also be a reference to the fact that Lil' Wayne represents the Bloods gang, which are affiliated with the color red; their rival gang, the Crips, are affiliated with the color blue. Hence, the "blue" rivals he/his gang kills would be "ghosts."
Lil Wayne is saying that if the rap business (or life) was a Pac-Man video game, he would be Pac-Man and you would be a blue ghost. In the video game, Pac-Man attacks ghosts when they turn blue (the blue ghosts also float/run away from him).
Another explanation could be that in Pac-Man, the only time the Ghosts flee from Pac-Man is when there Blue. Hence Lil Wayne is saying he is a constant aggressor towards anyone who opposes him.