That is how some referred to the Health Science Unit A shortly after it was completed in 1971, now officially named the Malcolm Moos Health Sciences Tower. The reference was to the then dean of the School of Dentistry, Erwin Schaffer. The school and dental clinics are one of the primary occupants of the structure.
I have heard others refer to the building as ugly, dark, oppressive, and Orwellian. But the most apt derogatory term would be brutal.
Moos Tower, Weaver-Densford Hall and the Phillips-Wangensteen Building, which comprise the majority of the health sciences complex expansion during the 1970s, are all examples of Brutalism in architecture.
The designation of Brutalism is actually derived from the French term for the style "breton brut," or literally raw concrete. The style, common from the post-WWII period until the 1970s, is usually marked by rough concrete or stone exteriors with protruding sections that underscore the functionality of the interior spaces over the aesthetics of the facade.
A 2008 story on NPR highlighted the love/hate people have for the brutal style and discussed the move toward designating many structures, to the dismay of the occupants, as historic landmarks.
Boston's City Hall, which has a strong resemblance to the U of M's health sciences complex, is one such building on its way to receive a landmark designation.
See also Brutalist Architecture on Flickr.