Now that it's out of the running, I want to say that while I don't think it's a contender for the top spot(s) in the saddest episode tournament, I think that Evergreen is a really well-done tragedy.
The episode opens with the setting of the dinosaur times, and we're introduced to the fact that a powerful being wants to stop a "cataclysmic" comet from hitting their planet. That fact alone sets the stage for a tragedy, because we already know that AT takes place on Earth, and everyone knows what happened to the dinosaurs. So you know right away that Urgence's plan is doomed to fail, but that doesn't stop you from hoping they'll somehow succeed, or lamenting that it didn't work with If Onlys. If only Urgence had taught Gunther magic. If only he had taken care of Magwood more thoroughly. If only Gunther had been able to control the crown by sheer will. If only Gunther hadn't admired Urgence so much. That alone marks a good tragedy, that you know it's going to fail but you can't help thinking it didn't have to be that way.
And then we get into the theme of the cycle of abuse. Urgence never loved Gunther, seeing him only as a somewhat useful assistant, someone to beat obedience into. But Gunther loves Urgence, and he thinks that Urgence loves him, because he's never experienced any other type of relationship with a sapient being. So he sees the abuse he's given, the insults, having dirt thrown at him, being struck, etc., as a form of love. We see this come out when he interacts with Nina. Gunther clearly loves Nina, but he casually calls her "blockhead" early in the episode, and hits her when she tries to comfort him later, all because he thinks that that is how you show love.
It's this abuse that ultimately undoes Urgence's plan. When Gunther puts on the crown, he becomes his idol, but the parts that he fixated on were less the ice magic and more the "love." So instead of becoming a powerful wizard, he becomes an abusive master, screaming nothing but "Gunther, no!" as he and everyone he loves dies.
Since the crown imprinted on Gunther's wish and carried Urgence's appearance on through the ages, it's likely that this abuse was also carried on, which may be where Ice King gets his meaner moments from. As Simon Petrikov, he's polite and kind, but as Ice King, he does all sorts of awful things, especially earlier in the show, such as kidnapping people and freezing them when he's displeased. These moments mellow out as the creators leaned towards making him a more likeable and sympathetic character, but the fact is that Ice King was one of the first villains of the show, and that may be all due to Gunther's love for Urgence.
Anyway. How do you end a post. Go rewatch Evergreen.
