The waters of California’s San Joaquin River Delta are currently suffering from an alien invasion. Fortunately, the creatures don’t come from outer space, although looks can be deceiving. Over the past several weeks, local boaters and beach-goers have been finding gelatinous brown blobs known as magnificent bryozoans (Pectinatella magnifica)—although people also call them moss animals or dragon’s boogers.

The bryozoans, which are actually colonies of tiny organisms called zooids joined together, aren’t supposed to be west of the Mississippi, as the Stockton Record reports. It’s not clear how long the alien species has been in California, or exactly how they got there. However, in 2012 the U.S. Fish and Wildlife Service also noted an increase in magnificent byrozoans in the Pacific Northwest, perhaps because of climate change. (Magnificent bryozoans need waters over 60 °F to survive.)

Locals residents and boaters have been alarmed by the creatures, which cling to docks and weeds throughout the Delta. But while their appearance might be disgusting, they won’t actually harm you. At least, not immediately. Since the bryozoans are an invasive species, as CBS Sacramento notes, they may be disrupting habitat for other creatures. Only time will tell what kind of effect they’ll have, but for now, at least we know they’re not from Mars.

You can learn more—and see the "dragon boogers" up-close—in the CBS video below:

[h/t: Stockton Record]

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