Ian was a non-corporeal lifeform which decided to investigate life aboard the Enterprise-D. The alien decided to assume physical form and impregnate a Counsellor troi in order to experience all stages of life. It grew extremely rapidly, being born after a matter of hours and rapidly passing through early childhood. Unfortunately the alien emitted a form of radiation which caused samples of a lethal plasma plague on board the ship to grow. Ian Andrew chose to end his physical life rather than endanger the ship. [1] 