Final answer:
Sea anemones are the plant-like organisms seen during the opening credits of Finding Dory, but they are actually predatory animals in the phylum Cnidaria, not plants.
Step-by-step explanation:
The plant-like organisms seen during the opening credits of Finding Dory are actually sea anemones, which belong to the phylum Cnidaria. Sea anemones are a type of predatory animal that is attached to the surface beneath them and have tentacles that they use to catch small fish and shrimp. While they may resemble plants, they are not actually plants.