Blue buttons are just one of the many small critters that live in the oceans. They are often mistaken for jellyfish or colored plastic when they wash up on beaches, but they are actually free-floating colonies of hydrozoa.
Blue buttons have two main parts: the central disk, which is about an inch across and yellow brown, is a hard flattened bubble that holds gas to keep the blue button floating. Attached to this disk are a type of bluish stinging polyp, which act as tentacles, although the blue button itself does not have a powerful sting—it can only cause minor skin irritation.
In the center of the disk, a larger central polyp acts as a mouth for food intake and waste removal for the entire blue button colony. Blue buttons eat live and dead small fish, eggs, and zooplankton.
The blue button cannot swim; it relies on drifting on currents and wind to move through the ocean.
Pretty cool, huh?