The Dolphin is an aquatic mammal who makes her appearance in "Memories of Boom Boom Mountain." She first appears while having a tea party with Jake. She also appears at the end of the episode when she has fallen in love with him. Jake thinks of it as a problem, but Finn says it is "the opposite of a problem." This is promptly followed by a scene involving Finn and Jake riding her across the water.
She looks like an ordinary gray dolphin.
- Even though normal dolphins cannot survive on land, this dolphin apparently can.