Biggest boss you have beaten

[Sizzle Montyjing]

Oooooh....
The Beast from InFamous 2 was pretty huge, also that other massive creature in InFamous 2...

Also... Star Wars: The Force Unleashed when you move that spaceship using the 'force'?
Does that count?

 

[Sizzle Montyjing]

Bloody hell...
Posts being eaten/ hidden left and right...

 

[TheGreatAndPowerfulZOG]

Final boss in Shadow of The Colossus. It's basically a living skyscraper.

 

[Kapri]

The bosses in Resident Evil games tend to be the size of sky scrapers and adorned with tentacles, so I'll go with the final boss in Darkside Chronicles.

 

[GundamSentinel]

Kronos in GOW 3

One of the Arms Forts from Armored Core 4 Answer, probably either Great Wall, Answerer or Motherwill.

I didn't exactly have a tape measure with me at the time, so either of those will do.

 

[scorptatious]

I would say most of the colossi in Shadow of the Colossus, but I remember most of the bosses in Bayonetta being pretty damn big as well. Especially the final one.

 

[Sombra Negra]

probably unicron from the 2004 transformers video game. dude eats planets piece by piece :3

 

[kasperbbs]

Probably the Titan from the 1st PSP GoW game, i didn't really kill him, but the poor guy was left there holding olympus or earth or whatever it was for the rest of his life or until another sequel that i havent played.

 

[Tigurus]

The rat in Battlefield 3!
...He looks big when crawling on the ground D=

Nah, uhm, I think Necron from FFIX or The Dragon God from Demon's Souls.

 

[dickywebster]

Pick a GOW boss, they all tend to be a bit on the large side and yet you can still kill them with two needles (in comparision).

 

[Eggbert]

Any of the bosses in Painkiller, really. Mainly Necrogiant and Satan, I think.

 

[Woeps]

The statue in Devil may cry 4 is the only boss i can think of. It was called the savior or Sparta I think.. can't remember which one

 

[CleverNickname]

The 2nd Death Star in X-Wing Alliance

ah, space. you dwarf all the puny ground-dwellers