Papulatus--One of a Kind

I'd put Papulatus, Griffey, and Manon (and that Leviathan thing) in one category because they're all roughly the same experience to fight. They're a lot larger than characters, they're mobile, they cast spells at stuff in front of them or in the area around them, and have a high KB so they're un-KBable by players who are in the intended level range to fight them (yes, we've seen BMs solo Pap by Puppeting and cornering him, but he was originally created for level ~100 third jobbers, who are typically unable to KB him.)

Also, where would you put the Feudal Lord boss? He's like a non-ranged boss, since ranged characters aren't realistically able to survive his hits without ridiculous levels of washing.