The largest species of dolphin is the orca, which can grow to 30ft+.
Dolphins eat fish and squid, locating them with echolocation.
They are very social animals that live in pods with a dozen or more other dolphins.
"Immortal jellyfish" can revert to their polyp stage (1st stage in life cycle) when in distress, making them "immortal".
Jellyfish are 95% water and only 5% proteins, muscles, and nerve cells.
Jellyfish can clone themselves and take over the world haha!