Flodhäst i vardagsrummet
It means "hippopotamus in the living room", as in a thing that everyone can see but no one admits is there. Hippo doesn't understand how anyone can ignore a hippopotamus, especially one as cute as him.

This is a Barnslig Flodhäst soft toy from IKEA. It must get cold up there if hippopotamuses have to wear stripy socks to stay warm. I wonder what the hippos do if their pools freeze over.