single word requests - How do I insultingly describe an extremely ugly building?

The building is shaped like a matchbox. Or like a beehive. Designs of this sort need very little engineering and less imagination. It's mostly glass and concrete. More glass than concrete. It is a residential building.

In order to make room for it, an entire block of 19th Century buildings (very quaint and very much in keeping with the city's spirit) was mercilessly razed.

A handful of half-hearted protests from the neighbors followed. Those were ignored. The local media assessed the situation and found there was nothing worth reporting.

The monstrosity went up in no time. It now towers over the street, faceless and depressing.

Because the windows are walls, and the walls windows, it costs a fortune to keep the apartments warm in the winter and cool in the summer. Not that I think the tenants give a rat's ass: to those who can afford to rent a place in that building, the utility bill of any size is a trifling matter.

Ordinary pejorative words that people normally use to describe this type of architecture (matchbox, barn, etc) are way too weak. The monster is just too hideous, and the architects who designed it, contractors who built it, and tenants who live in it are too self-complacent and too dismissive of things that are beautiful and harmonious, as well as of the city's history, as well as of other people who live in the city.

To summarize. The building is neither a barn, shack, nor a matchbox. Those words are much too weak. Any suggestions?

Addendum: I once called the whole "ugly growth" phenomenon "a chancrous rash on the body of American architecture," but that's too general, I think. Nor is it an exclusively American thing either: London is chock-full of them, and so is any German city, and Paris is catching up pretty fast.

Before: buildings not unlike these:

... and now:

Answer

You may refer to skin diseases like furuncle, pustule or carbuncle (mentionned by @JHCL).

Note that the carbuncle cup is a British award for the ugliest building.

For example, Woolwich Central was the "winner" of the 2014 Carbuncle Cup.