As many biotech investors noticed, shares of Affymax (AFFY) exploded yesterday, up 54%, with an unheard of amount of trading volume. In this video, Motley Fool health-care analyst David Williamson unwinds some of the rumors that may have led to this stock's jump, and warns investors that taking a position in this stock right now isn't investing, it's gambling, and you may be betting on a very shaky horse.