"Julia"is the song that Vicious' music box plays. During the war on Titan, Gren approached Vicious while he was listening to the music box, asking for the name of the song. Vicious tells him it is called Julia. Gren asks Vicious if he can play it on his saxophone back home when they get off of Titan, and Vicious gives it to him. Julia later reveals to Gren that the music box contained a solar transmitter. Gren mentions the song to Spike as he describes his encounter with Julia.