Trivia: Did you know...
That the Huragok (Engineers) are actually an artificial race created by the ancient Forerunners? They reproduce, or rather "build" new Huragok with available materials at their disposal.
They're a docile slave race of the Covenant that serve in uncovering and transporting Forerunner relics so that the Prophets may research them. Their ability to float about is because of gas filled sacs that make up most of their body. They're able to communicate by deflating these sacs as well as with sign language and clicks and whistles.