While at first you may be thinking this is simply a blow-up animal, or balloon, this ain't helium-filled latex. It's alivveeee -- and more than that, it's actually four living things working together to form this curious blob.
This is the famed Portuguese man-of-war jellyfish.
The creature is a siphonophore, which is the scientific name for a community of organisms working together to resemble a single organism.
The sac we see here is inflated to keep the man-of-war floating on the surface of the water, where it normally hangs out. Its tentacles deliver a notoriously painful sting to humans that it uses to paralyze fish that it eats -- yes, this empty bag eats.
The Portuguese man-of-war usually lives in tropical, marine waters, and this particular one washed up on a beach in Olivenca, Bahia, Brazil, according to the video description.
So next time you are walking along the coast of Brazil and see a balloon, do a double-take. It just might be an animal.