Braco isn't actually the antagonist in this episode! He's surely a nuisance to Bubblegum, but the real antagonist is...
After PB met Braco, she was already annoyed with his presence. She summoned Finn and Jake to go after a soul stone, which was needed for a cloning experiment she was conducting. However, Braco wanted to do it to gain PB's love. After doing so, he happily presented the soul stone to PB, only to find that PB found an alternative solution to her experiment. He was saddened, so he went to Peppermint Butler (in his "darker" side) for advice. The possessed form of CB wanted free, so Peppermint Butler used some dark magic to make Braco a "love magnet" in return of the freedom of CB. In the end, Braco was uglier in appearance, but PB gave an exact replica clone of herself (known as the "Bubblegum Bot" to Braco, so he could be happy (which he was).
Also, there are small/minor appearances of Phil (cameo), the Morrow, and one of the Gumball Guardians.