Which monster do you find most irritating and why?

[Neo1989]

Oh if we include bosses Olga Flow's second form is a real pain. Even at Level 53 he killed me in one hit, think it was a form of Megid when I was stood under him. Luckily I had a Scape Doll, the first forms a piece of cake, just use a handgun or Rifle type and shoot him. The same for phase two but keep well back and off to the side when he stops to charge Megid. Dark Falz posed no threat.