Size

You could say 058 was Dr. Scott’s “pet project,” insofar as any car-sized heart-monster could be considered a pet. The so-called "Heart of Darkness" fascinated Dr. Scott, though not because of its incredible destructive capabilities. They had plenty of unkillable, inexplicable monsters at the Foundation, but only one of them had been spewing vaguely nihilistic word salad 24/7 for the last "██" years.

http://www.scpwiki.com/the-drooling-path-part-1