A lonjunction (lazy conjunction) of the two words "stupid" and "spectacular". It essentially means stupidly-spectacular. It can have either a positive or negative connotation depending on it's use.
"Sometimes he doesn't think about what he's doing and still manages to win in a stuptacular way."
"Letting Rich borrow my car was a stuptacular idea... he just crashed it into a tree."
All the cursewords, insults and adjectives you possess. Your rage distilled into the words you use to express it.
His spurnacular was quite large: so he called the object of his rage a filth-ridden-gunk-trumpet, that's only purpose was fail abysmally at everything it tried to do.
He has a pathetic spurnacular, so he can only call other people pussies and faggots.
To take something small, that doesn't quite qualify as a theft. Probably from the Danish "skæv" or the Dutch "scheef", both of which are pronounced similarly, meaning "askew, or not quite right'. To change an item's ownership without permission, but only something small and of little worth.
"I skeefed an apple off the neighbor's tree." "I skeefed some chips outta your bag when you looked away." "Don't skeef my chair when I go to the bathroom."