10 Most Emotional Avatar The Last Airbender Moments

We have already addressed how emotional it was to see Aang's response to losing Appa, but the moment of his capture is even more painful to witness.

In the episode The Library, we watch Toph struggle to fight off sand benders whilst keeping the titular library from sinking into the ground with the rest of the gang in it. She is forced to decide between saving the team, or saving Appa, and unfortunately has to choose the former.

What is mainly tragic about this is that thus far there's been a strange sense of dissonance between Appa and danger. Although they frequently find themselves in awful situations, Appa never truly felt at threat. The closest we had seen were the water benders in the swamp trying to eat him, but he managed to evade them moderately well.

This is the first time we see that Appa is not untouchable, and the nature of how he is captured is gut-wrenching as there is an overall sense of how powerless anyone is to stop it. The scene is only further developed when Toph utters to herself "I'm sorry, Appa" as she stops fighting to save him.