The crew of the Enterprise must stop a living planet consuming cloud before it attacks an inhabited world.



(created by),


Add Image Add an image

Do you have any images for this title?



Episode cast overview:
Capt. Kirk (voice)
Mr. Spock (voice)
Dr. McCoy (voice)
Sulu (voice)
Uhura (voice)
Cosmic Cloud (voice)


A huge cosmic cloud is reported moving into the outer fringe of the galaxy. Starfleet Command sends the Enterprise to investigate. Sensors indicate it is a strange combination of Matter & Energy. It seems to engulf and feed on the energy of planets. It makes a deliberate course change to head towards the populated planet of Mantilles indicating that it could be intelligent. Kirk sees it as a threat to every planet in the galaxy and if they can't communicate with it and make it stop it will have to be destroyed. Written by tomtrekp

Plot Summary | Add Synopsis

Plot Keywords:

23rd century | See All (1) »



Official Sites:



Release Date:

22 September 1973 (USA)  »

Company Credits

Show detailed on  »

Technical Specs


| (technicolor)
See  »

Did You Know?


Though Robert Wesley was played by Barry Russo in the original Star Trek series, James Doohan provided Wesley's voice for this episode. See more »


When Commodore Wesley appears on the computer monitor in Kirk's quarters, Wesley's shoulder is visible on another, separate view screen right next to him. See more »


Captain James T. Kirk: Judging from the disappearance of Alondra, the cloud lives on the energy it converts from the planets it consumes.
Mr. Spock: Exactly. It is like a huge bull grazing here and there in the pasture of the universe.
See more »


References Star Trek: The Ultimate Computer (1968) See more »

Frequently Asked Questions

This FAQ is empty. Add the first question.

User Reviews

Rather familiar but with a totally silly ending.
9 April 2015 | by (Bradenton, Florida) – See all my reviews

This episode of the animated "Star Trek" is very reminiscent of several other Trek episodes--particularly "The Doomsday Machine" and especially "The Immunity Syndrome". Because of its familiarity, Trekkies will probably like it since it seems much more like a real Trek show than the previous episodes. On the other hand, it's not exactly original and the ending is pretty stupid.

There's a planet-eating cloud in space. It's going to eat Mantilles and kill millions unless the Enterprise can stop it. But there is a problem--the Prime Directive doesn't want Federation craft killing other life--and the cloud is alive! So what will they do? Yup-- call on Spock to do a mild meld with this thingie and ask it to leave, of course! You just have to see this part of the show--it's unintentionally funny.

I gave this one a 5 because like all these cartoons, the animation totally sucks and the story idea not exactly original.

1 of 3 people found this review helpful.  Was this review helpful to you?

Message Boards

Recent Posts
In the long run, is this series worth it? gollumsmeagolrocks
Yesteryear - Timetravel huh? Ezel
First Saucer Sever...? clay56
The Slaver Weapon: A great ep gavbrown01
Is there any place i can watch these on the internet? billyshears-2
sympathy for the devil episode... horrendous mothfodder
Discuss One of Our Planets Is Missing (1973) on the IMDb message boards »

Contribute to This Page

Create a character page for: