Star Trek TOS The Devil in the Dark.
Great episode, great Kirk and Spock interaction in this episode. When Kirk basically tells Spock to go back and help Scotty, the ‘emotion’ that Spock portrays is perfect. Kirk is worried that Spock won’t kill the creature if necessary. Then when Kirk is alone with the creature Spock tells him to 'shoot it!" but Kirk does NOT, because it isn’t threatening him. (it’s already killed many men) Finally they talk to the creature via Vulcan mind meld and we come to realize that the Devil in the dark is the humans on the planet. Second choice Arena for the same reason that we have to figure out when we are the bad guys because we are the bad guys sometimes.
I think a really good example of this type of TOS episode was “Balance of Terror,” the one with Kirk vs. the Romulan Commander. One of the best TOS episodes of all three seasons, IMO.
Batman: The Animated Series: “Appointment in Crime Alley” is driven by two of the major elements of the Batman mythos: his tragic backstory and the ongoing wretched-hiveness of Gotham City. He can win some victories and save some innocents from the latter, but not defeat it completely (highlighted by Daggett walking away scot-free).