Adventure Time came to an end on Monday after 10 seasons with a series finale that featured some intense and standout moments, delivering what fans have wanted while leaving the door open to further stories. But arguably the most crowd-pleasing scene came after Princess Bubblegum was seemingly crushed by a monster, which sent Marceline into a frenzy at the potential loss of her best friend.

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However, when it was revealed that Bubblegum survived the attack, the two shared an emotional exchange in which Marceline states how scared she was at the thought of losing her. Just before the two return to battle, they share a kiss.

Executive Producer Adam Muto spoke with TVLine about how that key moment came to be, saying a relationship between Bonnibel and Marceline had been an "ongoing conversation." When one of the storyboard artists was outlining the episode, she referred to the two characters sharing an "emotional moment." A note next to the scene stated, "Come on!"

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"That was the only note," Muto recalled. "I can't argue with that."

Fans of the "Bubbline" pairing will be more excited that Muto said it "wouldn't be incorrect" to assume the two began an official relationship. He didn't want to make the details too specific, but a scene near the end of the episode that depicts them cuddling on Marceline's couch all but confirmed that.