Speculation exploded. Were they sea creatures? Exotic amphibians? Turns out, they were Arion rufus—red slugs—caught mid-mating in an incredibly rare moment few ever see. Red slugs are hermaphrodites, meaning they have both male and female organs. Their mating is a slow, coordinated dance of mutual fertilization that can last for hours—a fascinating, if slimy, spectacle of biology in action.

Though often overlooked, these slugs play a vital role in their ecosystems, helping break down organic matter and recycle nutrients in damp forests and gardens across Europe and North America.

What made the moment special wasn’t just the biology—it was the shared curiosity it sparked. In a matter of hours, a Reddit post transformed into a global learning moment, blending everyday wonder with scientific insight.

This viral encounter is a reminder that nature’s most incredible stories are happening all around us, often just out of sight—until curiosity brings them into view.