Kingdom Hearts: Cursed Merman Spell

Sora and his friends are taking a break on Destiny Islands (just before the events of KH3). A mysterious half women half octopus appears from the ocean claiming to be Ursula's sister Morgana. Sora, Riku and Kairi summon their keyblades to battle her and her minions Undertoe, Cloak & Dagger. Completely unaware that Morgana had brought something with her.