The cell phone belongs to Daphne Blake. It has a light and camera feature.
Scooby-Doo! Mystery Incorporated
Daphne called her mother to pick her and the gang up when they were stuck in Gatorsburg.
Fred Jones, Jr. borrowed it to take a picture of the Ghost Truck's tire tracks. Rung Ladderton then rang about his date with Daphne, with Fred taking the call on her behalf.
She stayed after hours at Crystal Cove High School's library to do research on the missing kids, when the lights went out. She used her phone's light app to see.