Flame Jester is the jester of the Fire Palace seen in "Incendium." In his short time on screen he dances and laughs. Jake accidentally kills him by throwing the first of "Prince Finn's" gifts, a water bottle at him. Flame King is quick to blame "Prince Finn" for smiting his jester, though he quickly follows this up by saying that he hated his jester. Jake claims that "Prince Finn" also hated the jester, and nobody seems too concerned about the affair. Other than Flame King the only character who reacts at all is Flame Princess; she seems disgusted when Jake first kills the jester. However, after Flame King states he hated his jester Flame Princess seems impressed "Prince Finn" would kill him.
Flame Jester's entire body is orange fire, and he is about the size of Jake. The top of his head resembles the hat of a medieval style jester. The inside of his body has a yellow shape from his head to his belly that resembles esophagus and stomach. When he is melted the yellow shape turns to a puddle, his orange fire-body turns to steam, and only his eyes and mouth (with teeth and tongue) remain unaffected.
- In the original storyboard, his name was Heaphester.