Alpha Carinae V
Alpha Carinae V is the fifth planet in the Canopus system and home to the creature Drella. (TOS: "Wolf in the Fold")
The Drella of planet Alpha Carinae V derived nourishment from the emotion of love or fear. The Drella exist without form in conventional sense and is a mass of energy of highly cohesive electromagnetic field and very similar to Mellitus, gas cloud creature of Alpha Majoris I, and Redjac that existed for centuries by journeying from planet to planet, including Earth, Mars, Alpha Eridani II, Rigel IV, Argelius II and Deneb II. (TOS: "Wolf in the Fold")
The Drella were able to possess human beings and take complete domination of their bodies. It was also determined that they could somehow 'possess' a computer as happened aboard the USS Enterprise.