That's a part of the famous building designed by Friedensreich Hundertwasser. What kind of a building is that?

The Hundertwasser Toilets is a public toilet located in the town of Kawakawa in northern New Zealand. The structure was completed in 1999 and named after architect Friedensreich Hundertwasser, who conceived the project. It is one of the few toilet blocks seen as an international work of art and a tourist attraction in its own right.