Wildlife officials across the U.S. are alerting residents to the presence of strange “alien egg pods” in murky lakes and rivers—gelatinous, jelly-like sacs that are actually harmless aquatic creatures known as bryozoans.

These gooey organisms, capable of cloning themselves, are sticking to rocks, docks, and submerged branches, prompting widespread social media speculation and jokes comparing them to alien invaders or body snatchers.

Despite their eerie appearance, the Oklahoma Department of Wildlife assures the public they are native, pose no danger, and are indicators of healthy water quality. Bryozoans are colonies of tiny invertebrates called zooids, each only 4 millimeters long, that filter feed by straining particles from the water.

Dating back 470 million years—older than dinosaurs—they reproduce by cloning and release statoblasts (egg sacs) to survive winter. They’re found on every continent except Antarctica and help support aquatic ecosystems by serving as food for snails, mussels, and small fish.

The U.S. Fish and Wildlife Service describes them as similar to coral but more fragile, with chitin shells that can harden and preserve the colony when dried. While their appearance may unsettle swimmers, wildlife agencies emphasize that these creatures are essential parts of freshwater ecosystems.