Beware of Vulcans wearing beards! This cheeky "Star Trek" t-shirt features the legend, "Do you know your Spock?" alongside prints of the trusty Spock of the United Federation of Planets side-by-side with the sinister bearded Spock from the Mirror Universe's Terran Empire. Each Spock is helpfully labeled "Good Spock" and "Evil Spock," just to ensure that the two are never mixed up.