Crustaceans: Crab
Mammals: ~~Weasel~~ Crab
Plants: ~~Tree~~ Grass. Everything grass.
Amphibians & Reptiles: ~~Unchanged because they are perfect~~ Crab
Birds: ~~360° around back to dinosaurs~~ First of all, avian dinosaurs are dinosaurs. Secondly, 360° doesn't really make sense, probably they meant 180°. Finally, crab.
Fungi: I shan't speculate on the affairs of gods.
Moral of the story: You might not like it but decapods are peak animal evolution. All roads lead to crab.