'Fithos Lusec..' appears in several places in Final Fantasy VIII, once as the only lyric to the song "Succession of Witches" (and I think maybe one or two of the other witchy songs), and another time in "Liberi Fatali", the song in the opening sequence.
It's also in the box art somewhere, I think behind the last disc you see the sorceress with the phrase in front of her.
(Minor correction to skid: "Fithos Lusec Wecos Vinosec" is not the only lyric in the game. There's the rest of Liberi Fatali, and Faye Wong singing "Eyes on Me".)