I spotted this at my daily commute - going by bike, it's easy to get off and investigate..
Looks like a huge, "breathing" flower, a bit like from an Alien movie. Also has an spect of making one feel a bit uneasy/uncomfortable, in Japanese I would say "違和感".

It's part of the "The vanishing point of the Ant" exhibition.

@globalc Fühlte mich an diesen Pilz [!] erinnert, den ich in einem nahegelegenen Park entdeckt habe. Offenbar heißt er "Gemeiner Wetterstern", erschien mir aber eher oktopoid...