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Tear Jerker: Wander over Yonder
In "The Fugitives", the heartbreak on Wander's face when he thinks Sylvia's abandoned him.
In "The Good Deed", Wander is so disheartened by his failed attempts at helping others that he lets himself sink into the mud as a missile heads for the sun.
In "The Pet", Sylvia thinking that Wander's been killed by the alien.
And when she mourns him, she recites what he would have to say to her: "It's always sunny somewhere, Sylvia old girl. So keep your eye on the horizon and don't look back. Never look back!"
In "The Box", Wander thinking he has let Sylvia down for not believing he can overcome his temptation of opening the box.
In "The Hat", Sylvia spends most of the episode being so sure she knows where Wander is, and when she finally gets there, after receiving a call from a drowning Wander, it turns out she's wrong. And she's just devastated, falling back in despair, feeling she's too late to save her friend. To make matters worse, the phone call was just Wander telling her he'd always love her, and then a gurgling, barely-heard "goodbye" as water covers his head.