Jake's phone

Jake's phone is a Walkie-talkie with a headset, powered by batteries taped to the back of the phone and connected to two wires. Presumably, it was made by Jake. There is also a number pad to dial phone numbers, as well as up and down arrows to scroll through his contact list. So far, it has only appeared in four episodes:


 * "My Two Favorite People," where Jake uses it to call the Cloud Kingdom and Tiffany


 * "Loyalty to the King," where Jake tries to make a call but is blocked due to the large number of people simultaneously using their phones


 * "Her Parents," where Jake speaks to Lady Rainicorn at the beginning of the episode about her parents' coming to visit him later


 * "Go With Me," where he uses it to call Marceline

List of contacts
Jake is known to have at least 27 contacts on his phone:
 * Benton
 * Captain Majesty
 * Cloud People
 * David
 * Dennis
 * Doug
 * Finn
 * Gareth
 * George
 * Hot Dog Princess
 * Jennings
 * Jerry
 * Lady Rainicorn
 * Larry
 * Luke
 * Marceline
 * Mike A
 * Mike H
 * Mike R
 * Mr. International
 * Mr. Outrageous
 * Pete the Punk
 * Peter
 * Princess Bubblegum
 * Reggie
 * The Flying Lettuce Brothers
 * Tiffany