short for "que es?" in spanish.
it originates from a '90s/00's spanish television network called Telemundo.
it was basically a spanish seasame street. in one skit, a giant monster would show a common item such as a glass of milk and then ask the contestants, "que es?"
this became so gay after repeated viewings that it has been abbreviated to a more phonetic
english spelling of simply, 'KS'.
when someone says something
really stupid or ask a totally befuddling question, it would be
appropriate for a response of a long drawn out, "K......S?"