In the one-shot "Nigel and Eva's First Meeting", the mariachi band was floating in the pool at Sector J after Nigel and Eva Roberts met and talked for the first time. Gamewizard then ordered them to get back in Operation: GALACSIA, for they weren't supposed to be there in that time.
They also partially narrated The Great Galactic Race, whenever the racers finished or started a segment, then asked questions relating to Gamewizard's series. When the final segment began, they were run over by Nick's Revenge Rider, and weren't seen again.
In Operation: NECSUS, the mariachi band became famous throughout Galaxia for their music, and their 15th anniversary was celebrated. They had been stalking a record dealer, who enjoyed their music and became their manager.