Medford youth theater company Spotlight Productions presents the first of four performances of “The SpongeBob Musical” at Medford High School’s Marsha Caron Theatre. Dive into the underwater world of Bikini Bottom with all your favorite characters, catchy songs, and hilarious adventures. Tonight’s show features the  “(Not) A Simple Sponge” cast, which also will perform at 7:30 p.m. on Saturday, September 14. The “Super Sea Star” cast will perform at 7:30 p.m. on Friday, September 13, and at 2:30 p.m. on Saturday, September 14. Tickets are $20 for adults and $15 for students Purchase tickets for tonight’s show through Eventbrite.