Strange. The object seems real and perhaps five sided? It does not react like a balloon and seems to be fascing the same way throughout the vid, but that could be wrong. The pixels were jumping about a bit.
It would be interesting to hear what others think it is.
My husband and I saw the exact same thing hovering over the “Serra do Mar” (mountains that run parallel to the Atlantic Ocean coast) in Parana State, southern Brazil. It moved slowly towards the capital city.