You're so goddamn right that it's not even funny. But anyway...
Anyone remember Dark Link from Zelda: Ocarina of Time? DAMN, I hate that bastard. Everyone was like "Just use the hammer!" and you know what? I used the hammer. And it didn't work. He either used his shield to block it, or stabbed me before I had a chance to connect. Then everyone told me "Damnit, man! Just use magic!" and you know what? I used magic. I spun around with my flaming magical sword so many times that it made me dizzy. Then I ran out of magic power, realized I had no green potions left, and died. Then they're all "No, you ass! The OTHER magic!" so I used Din's Fire. The bastard STILL kicked the shit outta me, because I kept running out of fooking magic!! I swear to God, that little Dark Bastard still pisses me off. Because, for some unknown reason, he suddenly became massively easy. I finally connected with the freaking hammer, and then it was child's play. He never came back from that first blow, I just kept whacking him before he recovered. Go figure.
Other than that.... Anyone remember a weird little NES game called "Mechanized Attack"? You were this commando guy sneaking (with machine guns blazing) onto this island where evil guys (either Nazis, Communists, or terrorists. I can't remember which.) that were making cyborg soliders. DAMN, that game was hard. I'm not sure if I'm remembering this right, but I believe the last boss was this giant brain thing in a glass tube. With rocket launchers installed on the sides. Now why the HELL would some asshole brain in the middle of the most heavily-guarded place on the planet need fucking rocket launchers installed on the sides of his tube!?! I abhor that thing. He took about 300 gernades, 23 hundred rockets, and every single machine gun round I had on me before he went down.
And while I'm on the subject, I hated the final boss of Yoshi's Island. That game ROCKS, by the way, but I hated the end boss. It was baby Bowser, GIANT SIZED!! He threw something at you. I can't remember what they were, but they kept taking chunks out of the platform I'm was standing on. And as he's throwing these things at you, he's coming closer. If he gets all the way to you, then you die. Instantly. Game over. So there.
Now, if you want to decide who the FUNNIEST boss is, that's a whole different story.
Once again, Yoshi's Island deserves a mention. Every once in a while in that game, this magician guy would pop up and use his uber l337 magic skillz to turn a regular enemy into a boss of some kind, usually by making it really really big. At one point, he appears as usual, with your friendly neighborhood soon-to-be-boss enemy a simple froggie. So, he says his thing and drops the happy magical dust as usual... But then, YOSHI SHRINKS! The froggie eats him, and -poof-. There's your boss battle. You're inside the frog's stomach, and you have to launch eggs at the little thingie hanging down the back of his throat while dodging drops of stomach acid and eating the shyguys that pop up in order to get more eggs. Not only was it quite difficult, as I remember, but it was also increadibly amusing.
And yes, this is my second reply to this thread. So sue me.
Edit: Oh yeah, lefty? Can you do me and the rest of the world a favor? Change that fooking sig, man. It's quite large, quite low-quality, and quite annoying. And it's not even that funny. Thank you, and good night. *bows*