The Pennsylvania Fish and Boat Commission and Department of Environmental Protection are reminding people who go out on the water what to do to prevent spreading the invasive alga didymo, or 'rock snot'.

While it looks super gross, rock snot is not harmful to humans, according to a report by CBS 2. It can, however, cause a lot of ecological problems.

It has the nickname "rock snot" because, well, look at it. But, CBS 2 reports that when the water is squeezed out of it it actually has the texture of cotton or wool.