the most annoying video game boss i have ever fought is the last boss on rayman DS. its this huge robot in a lava bit that you fight while riding on a rocket that blows up the minute you touch something. and the only place you get ammo from he floods D: still haven't beaten him.
King Dedede in a game of kirby... You must hit him like 200 times and the only way to do a damage to him is by bringing a box with something inside and damage him like 200 times...Also while your bringing it to him if you fail you watch a movie of like 10 seconds or if you success its the same thing... And plus if you loose you give him money OMG!!!
That Blob that changed elements in FFX Demyx in KHII Ansem in KH (last battle) Belias in FFXII, not that hard, but gave me a lot of trouble > Any boss in Need For Speed: Carbon...you can't stay on the road >
Seriously? No one else has brought this up? I'M the one that has to say it? Alright. Perhaps the most infamous god-boss in all of classic gaming, Mike Tyson on Mike Tyson's Punch-Out.
The Thorax from Mass Effect is definitely the most annoying boss I've ever had to beat. You have to run up to different levels of this building while destroying parts of the Thorax. Every time you destroy a part of it, weird zombie-things wake up, and an Asari clone pops out of the plant. It's pretty bad, because sometimes you won't realize that the clone is right behind you, and then it will stun you.