Animated short film, surreal, I believe French, also probably over 30 years old. Clips of it were featured in some small bands music video who’s ads were on Instagram about a year or two years ago (that’s where I first discovered it). Full film is on YouTube I believe. Not Fantastic Planet, but that seems to be the only result Google gives me. Plot goes something like this: boy and a girl are sailing in a boat across a calm sea. They find a large castle/town island. They explore it, it seems to be abandoned. Strange humanoid creatures secretly live there and are watching them. A mysterious woman creature lives in the top tower of the castle which fascinates the boy who sees something shining from it. One night, a whale-like corpse washes up on the front gates. It turns into strange woman-like creatures that dance away. At the end, the boy and girl go back in the boat and sail away. Any help to find this is appreciated. Thank you!