Lumpy Space Princess's phone first appears in "Trouble in Lumpy Space" when Lumpy Space Princess calls her "BFF 66," Melissa, who reminds Lumpy Space Princess of that day's Promcoming dance. Lumpy Space Princess later takes out the phone in "Loyalty to the King" when she calls Peanut Princess to tell her about the Nice King. In "Heat Signature," Lumpy Space Princess talks to Melissa about how well she is doing all on her own. In "The Creeps," she uses it as a source of light after the lights go out. In "Gotcha!," she has a new phone, which she uses to contact Turtle Princess.
It is red and rectangular, with a blue screen and a light blue antenna. In "Gotcha!," her phone is black instead of red, but it looks the same otherwise.