sketch

comes from the word "sketchy"
commonly used in terms as an adj, originated in California

and is soon to be used nationwide.

it is used to describe an intensely scandalous situation or something outrageously unbelievable.

boy: Heidi and Spencer Pratt weren't at the Hills series finale!
girl: OMG shut up?! that's so sketch

example 2

girl1: I wasn't invited to my best friend's party of the year!
girl2: eeee that's so sketch