Wildlife officials across the U.S. are alerting the public to unusual, jelly-like sacs spotted in murky lake and river waters. While these sticky, translucent blobs may resemble alien egg pods to the untrained eye—and have sparked panicked reactions online—they’re actually harmless aquatic creatures called bryozoans.

Photos of these gooey masses have gone viral, with users comparing them to body snatchers or alien invaders. One user joked their child thought they were waiting to hatch and take over human bodies. Despite the bizarre appearance, officials are urging calm. According to the Oklahoma Department of Wildlife, bryozoans are native and pose no danger to humans or wildlife.

Bryozoans are colonial invertebrates that have been around for over 470 million years. Each sac is formed by thousands of tiny creatures called zooids that clone themselves and build soft chitin shells underwater. They attach to submerged rocks, branches, or docks, filtering tiny particles out of the water for food.

These colonies serve a useful role in aquatic ecosystems. As filter feeders, they improve water quality and provide food for mussels, snails, and small fish. Their presence is actually a good sign of a healthy water system. Although they thrive in summer, colonies typically die off in cold weather after releasing reproductive statoblasts that restart the cycle each spring.

Found on every continent except Antarctica, bryozoans might feel strange to touch, but they’re vital, delicate organisms—more coral than alien invader. Officials encourage curiosity, not fear, when encountering them in nature.