I am unironically convinced this is peak fiction.
Not a single thing about this anime is wrong, it's masterfully crafted from the wiggling seaweed buildings to the CGI sea urchins. The best part was the music though, such an epic track that suits the epicness of this anime. A nice detail is the close-ups they do on the sea urchins mouths (I think those are mouths idk I haven't looked into sea urchins). Each piece of the building being sucked into the sea urchin looks masterfully crafted, each frame of the building disappearing is elegant and much better than anything I've ever seen.
The only thing holding this back from a 10/10 is that it's short, if it was longer than 1 minute this would've been a 10/10 from me.
This is something you will NOT regret watching, unironically peak fiction.