Best fighting game bosses

[Brian]

What are your favorite bosses in fighting games? These can be final bosses or even mini-bosses as long as its a boss character.

Shao Kahn (Mortal Kombat)
Onaga (MK)
Goro (MK)
M. Bison (Street Fighter series)
Abyss (Soul Calibur 3)
Inferno (Soul Calibur 2)

[Peanut]

Whatever the boss was at the end of Killer Instinct Gold on N64. I remember my friend fighting him for about an hour, never figuring out how to kill him. That was kind of amusing.

[Kid Icarus]

Gargos ;). Yeah, he's a bitch... I can't remember if you could win by pulling a finisher on him or not, but we eventually figured out to knock his ass off the bridge.