This is a jellyfish.
The second one is the Nomura’s Jellyfish (Nemopilema nomurai). It is the largest organism in the phylum Cnidaria.
The third one is not flowers! They are also jellyfish.
The Porcupine fish- when it is in danger, it drinks too much water and swells so that the hunter can’t put it in his mouth. When it is taken out of water, it swallows air to do the same thing.