S1·E31 The Chameleon's Sting

A mad geneticist, Dr. Yates, attempts to create a lizard army, but is thwarted by the Centurions. However, during their struggle he accidentally injects himself with lizard serum and becomes a human chameleon, able to change form at will. He vows revenge on the Centurions, currently vacationing in Monte Carlo. The Centurions are not easily beaten, but when the enemy could be one of them, can even they win?