Rise of the Great Beast (1) - S1.E183

It’s the brawl for it all! All the monsters of Earth join forces with the survivors of the monster domain for an epic showdown against Grand Dragon Leviathan with the fate of both worlds hanging in the balance! But the tide of battle is turning against our heroes as Grand Dragon Leviathan unfurls gruesome tentacles to snatch Yugi and his crew and absorb them into its body!