WATCH: Locals Call 911 As ‘Body Parts’ Wash Up On Beach

Giant purple sea slugs—sounds like something that might attack out of a science fiction horror flick—caused quite a bit of panic among locals when oozing blobs of them washed up on shore. Some residents in East Bay, California, even called 911 to report the strange and unsettling visitors, after mistaking them for human organs washed ashore.

Fortunately—despite the resemblance to a human heart—the sea slugs are nothing to be alarmed about.  Also known as purple sea hares, the sea creatures can grow up to two-feet long and weight up to 15 pounds. They leak a purple hue of ink—which can look alarmingly like blood—that is not harmful to humans.

According to naturalists in the area, it is unusual to see the slugs wash up this early in June. Normally they are spotted on beaches during late summer months.

Sea hares apparently live for about a year and lay noodle-like eggs before dying. Usually by the time they arrive on the shore, the slugs are already dead.

Morgan Dill, who works for the East Bay Regional Park District warned that while it’s perfectly safe to gently touch or handle the sea slugs, residents should refrain from bringing them home with them.