An event, period, or entity that is incredibly unfavorable. The event, period, or entity is so bad, and keeps getting worse in such a way that it is spectacular. It leads people to wonder how this thing could have gotten so bad.
Bob: Jeez, I had a really bad day!
Jeff: Oh come on, it couldn't have been that bad.
Bob: Oh, it was. So bad, in fact, I'd have to say it was shittacular.