Who is your favorite "gimmick" boss?

I don't mind these type of fights because it takes a break from what you expect out of a normal boss battle.

Mine at the moment is The Black Rabbit Brotherhood (LoP) both parts. It can be frustrating at first but having three additional fighters rotating in and out keeps things fresh and fun to try to keep up with.

My gf hated this fight with a passion as she struggling with it but a year later she said they were her favorite in LoP because of the variety of attacks styles and their character designs.

What's yours?