Writer(s): Karl Geurs, Ralph Sanchez and Robert Sabaroff Director(s): Corey Allen
Walter Cotell as Kurt Mandl
Elizabeth Lindsey as Louisa Kim
Gerard Prendergast as Bjorn Benson
Synopsis: The Enterprise visits a terraforming station on Velara III where they encounter a new life form which, after being beamed up to the Enterprise for examination, attempts to take over the Enterprise.