It's documented in the book Google Plex. Google hired a neurosurgeon as their first infrastructure engineer. His fast task was to increase the rack density to save company money. The dude figure out how to pack 10x more processing power into the same size, resulting in overheating of the colo space (or overloading the power line? I can't remember exactly). The colo company had to tear down an entire wall and used a 18-wheeler modified mobile air conditioner. I probably got some details wrong as it's been years since I read the book, but you get the spirit.

Idk about this one, and 10x sounds past physical limits unless their original footprint was ridiculous, but I heard a story at Google that sounded kind of like this.

I think there was some colo in the day that charged only by sqft and gave away the electricity assuming customers would have reasonable densities. Somehow Google crammed a completely unreasonable density of machines into the colo. I would guess this was corkboard days. When the contract was renewed, the colo was sure to change the terms.