These units are the new Zerg units are being tried in SC 2 Beta. The units can be imagined like a chameleon which can imitate Zealot, Marine or Zergling. So enemy recon will be very easy for Zerg. Because in multi-matches there is no time to control your units’  count everytime, so any enemy leakage can be done which shall be crucial. But of course these units have a limited time to survive like Hallucination units in SC Original.