Earth is the water planet. It's mostly water.
The creatures are mostly water. And if anything, good or bad, happens to most of the creatures?
They just excrete various water-based fluids from their various holes. Different fluids for different holes and situations. Always water.
Many of them actually just live inside the water, and the ones that don't are extremely serious about absorbing the water into their bodies.
And like, if you remove their body-water?
They do not like that. As is to be expected of water creatures. From the water planet.












