In fairness, the boss battle music does play during the fight, though, which should be a tipoff. Boss in Mook Clothing: The Final Horizon appears to be a completely normal enemy wandering a completely normal area, but it's a very powerful Bonus Boss.Boss Banter: Malebaldur, Eve Angelus, and The Composer all do this.Bookends: Exhibited by the normal ending, where Ardus visits the exact same Mindscape location as in the beginning of the game.Arguably the Watcher of the Abyss does as well. Bonus Boss: Technically everything except Narrowden, but in the particular definition of "optional difficult challenge", the Final Horizon, Eve Angelus, and the Composer all count.
The Final Boss and the ultimate Bonus Boss share a special one. Battle Theme Music: " Rhetorical Battle " for regular battles and " War of Words " for Boss Battles.Unless, of course, you've found the well-hidden prismatic claw that restores color to the area, in which case he's a cakewalk. Barrier Change Boss: Narrowden is a clever example - his current weakness is telegraphed through his color, but as his area is Deliberately Monochrome, you have to guess every time he switches.Auto-Revive: The Reinvention skill gives this affect to whoever it's applied to.The bizarreness of this method of character creation is explored in the Edited for Content questline. I created Cynthia with a lot of the qualities that I find personally attractive (short hair, glasses, brainy disposition etc.).