One of Our Planets Is Missing
Series: Star Trek: The Animated Series
Airdate: September 22, 1973 | Year Set: 2269
Season 1, Episode 3
Summary
An enormous space-going cloud entity feeds on the energy of whole planetary systems, and a Federation colony is next in its path. The Enterprise braves its antimatter interior and finds a way to stop it. Spock mind-melds with the entity and tells it that it is killing life, and he persuades it to return to its place of origin.