Call them the flying pizza-things from hell. Or the rubbery suckers from another galaxy. But, whatever you do, don't let one of them attach to your back, sticking you with its alien stinger - you'd be in for some painful days. The final episode of the first season is a straight-out action adventure, a crackerjack alien invasion thriller. It starts out strong, with some ominous mystery on the nature of the threat, escalating to far-out alien monster attack mode. Though hampered by the standard cheesy TV SFX of the sixties, you gotta give the storyline some props for coming up with an unusual alien invader: it's basically a huge brain, but each cell is not physically connected - each cell flies about on its own, causing havoc. The low budget was also unable to show thousands of these things flying around, but that's what must have happened on this colony of Deneva (an actual futuristic city on display here, not just a matte painting - zowie!).<br /><br />There are some clumsy moments in the script and direction as the story jumps along. In one instance, after the landing party hears a woman's scream, Kirk orders everyone to 'fan out!' - but they run grouped close together. But, this is minor compared to some serious lapses in logic later in the episode. Spock, McCoy and everyone in the dozen science labs aboard the starship can't figure out a way to damage these alien suckers after hours of testing, despite being given a great clue by way of the sun; then Kirk idly latches on to a way at the last minute - maybe he was the only one being objective? Then they rush Spock into another test, with Kirk in full agreement, and blind him seconds before McCoy finds out it wasn't necessary. Kirk gives McCoy a 'if-looks-can-kill' stare and stomps out. Incompetence is really spread around in this episode. The writers tried to capitalize on the main trio's established relationship to create some extra tension, but it doesn't really ring true. Even Nurse Chapel becomes uncharacteristically testy during an operation, questioning McCoy on his methods. Well, she did become a doctor herself by the time of "Star Trek-the Motion Picture"(1979).<br /><br />In a way, the most fitting aspect about this being the last episode of the 1st season is that we're given the only glimpse of Kirk's real family (and its demise), outside the Enterprise. It's not much - Sam Kirk's only appearance is as a corpse and Kirk's sister-in-law dies soon after. Meanwhile, Kirk's nephew remains unconscious the whole time. It would have been nice to see them reunite at the end instead of the now-silly repartee on the bridge, as if Kirk doesn't even remember his dead relatives by this point (contrast this with the superbly grim ending of "The City on the Edge of Forever"). As mentioned, this is strictly alien invasion thrills, no more. Spock ends up with the best scenes, exerting Vulcan control over the obviously intense pain he suffers. I believe this was the only time Shatner played a character other than Jim Kirk or a Kirk-android or a Kirk impostor during this series. Even though the part was very brief, only as a corpse, he seemed to put every actor's effort into the part.