Toto was an American rock band who were very popular at the end of the 1970s and the start of the 1980s. They had hits with songs like "Hold the Line" (1979) and "Africa" (1983).
Zappa and Toto
On Joe's Garage Act I the Central Scrutinizer says near the end of Crew Slut: "And so Mary was enticed away from Joe by an evil barbarian with a wrench in his pocket, lured into a life of SLEAZERY with the entire road crew of some Famous Rock Group (I don't know whether it was really Toad-O or not...I don't know... I'll check it out). Again we see MUSIC causing BIG TROUBLE!"
The "famous rock group Toad-O" is a thinly disguised jab at Toto. On the original album, the track "Toad-O-Line" references Toad-O again, and features a guitar solo based on the Hold the line refrain. This track was later renamed on the CD version as "On The Bus".