Largest Boss in gamin

[Scarim Coral]

Well the largest boss well monster in Moner Hunter Tri is Jhen Mohran
However it's nothing like that when you face it since th actualy fight compose the four of you in that boat in the video (Jhen Mohran doesnt exactly smash it into bits).

 

[KingofallCosmos]

Not technically a boss, but I've got to stay true to my username...

Royal rainbow!

 

[Thetwistedendgame]

Someone should design a game completely based on trying to fight a world sized enemy, spending the whole game trying to take out it's limbs crawling with... More enemy.

 

[GartarkMusik]

Jubileus (?) from bayonetta is pretty huge, (at least I think that's the name, the end boss.)
It's bigger than every planet, and you can only kill it by kicking it into the sun.

Damn, Ninja'd. lol. But yeah, Definitely Jubileus, followed pretty closely by Mundus from the original DMC (same size, maybe? I dunno)

 

[SideburnsPuppy]

The final boss in Sin and Punishment.

The Earth

 

[WorldCritic]

Cronos from God of War 3 since I couldn't think of anything more original.

 

[Sebster 105]

Lucifer in painlkiller

 

[Ricotez]

The biggest boss I've ever fought in a game was probably Quadraxis in Metroid Prime 2.

Fun fact about Quadraxis: Metroid Prime 2 was the game in the series where there were two versions of the world, a light version and a dark version. You fight Quadraxis in the dark version of a very big room in front of an important temple; you pass through the light version of that room long before having to fight him, but when you do, you can see colossal spare parts for him lying everywhere (you can even use the Spider Ball to climb the magnetic rail on one of his spare legs to reach a door, valuable practice for the boss battle where you have to do the exact same thing). Looking at the parts scattered around that room in the light world gives you a very good idea of just how freaking huge Quadraxis is.

 

[Sora112112]

You guys could probably name one better than this one, but compared to the Investigation Team, Izanami-no-Okami is huge...

Same with Nyx(not Nxy Avatar) compared to Minato

 

[Darth Rahu]

Colossi from Shadow of the Colossus, The Black Emperor's giant robot from Viewtiful Joe 2, and the final boss from Bayonetta. All in that order from smallest to biggest.

 

[JackandTom]

The Riftworm in Gears Of War 2;

It might not count though as it's not technically a "boss fight"

Spoiler

You kill it from the inside. The spoiler tag probably wasn't nessasary but what the hey.

Also, apologies for the crappy image, it was the best one on google images that showed it's size.

 

[Yokai]

Spoiler: Prototype spoilers

Eliabeth Greene was the biggest boss in any game I've ever played. Gigantic tentacled worm that completely trashed Times Square; fun stuff. Unfortunately, Google Image Search turns up only two pictures, and they both suck. Unsurprisingly, the internet is more interested her human form.