Can have multiple meanings. Used used as a replacement for "who cares" or "whatever", or "it's all good". Has evolved to also mean "woah, check out that hot chick right there" and as an exclamation of pain or frustration.
Derived by high school students after seeing the worst play ever for extra credit called "Scapino", and was originally used afterwards to elicit laughter by bringing up the play as a reminder of a pointless and utterly wasted night.
"dude, I just failed my exam."
"hey man, scapino
"woahh check out the scapino
"damnnn she fineee"