Arthur

Arthur is a Jester-themed mini-boss with 75 HP found in The Alley, The Desert, and The Lab, unlocked after completing The Rift. Each turn he casts Metronome, which fires off a completely random spell from his pool. This unpredictability is the central challenge: his pool includes high-damage spells like Split the Atom, meaning he can potentially wipe the entire party on his very first turn with no warning.

There is no consistent optimal strategy since his actions are fully random — the wiki notes that save-scumming is a viable option, as changing equipped items on cats between attempts alters the random number seed and changes which spell Metronome selects. Arthur resembles the Jester class but does not match its color scheme. He has Robo and Champion forms in addition to the base variant.