Gaining permanent control of a Chryssalid/Tentaculat

In order to gain permanent mind control/molecular control over a Chryssalid or Tentaculat, mind control/molecular control a zombie and shoot it.

The tentaculat/chrysallid that will appear that turn is hostile, but don't kill it. Next turn, and for the rest of the mission, it will be controlled by you without additional mind control actions.

If you lost a soldier/aquanaut to make the zombie he will be back after the mission if the controlled alien survives.

It can also be zombified (by being attacked by an alien controlled chryssalid) and recontrolled (as long as you can mind control its zombie form)- effectively regenerating its lost health. However, each time this happens, you lose morale and the counter for the number of X-Com soldiers lost on that mission increases as if it were a different soldier being killed. So you may go in with 10 soldiers, but leave with 10 and -5 casualties. [NKF]