Calvin Decker

Calvin Robert Decker II was the name given to a alien lifeform in the 24th century.

In 2365, this lifeform entered Nelan Decker's body, allowing her to give birth to the lifeform, naming him Calvin after her father. It wished to experience Human emotions and more after it was "born". In one day, it grew from a baby to a 10 year old boy.

However, it caused harm to the crew, causing a plasma plague to fail. The only way he decided to save the crew is by dying. And then he returned to his natural form. (TNA: "The Unexpected Child")