In the spring and early summer horseshoe crabs come ashore to spawn. Wave action flips the crabs over where they are left to die in the hot sun, thus the “Slaughter of the Crabs.” The most colorful story has to be of Indians attacking early settlers in the area.

The naming of Slaughter Beach, Delaware, is a subject of local debate with several competing theories. The most scientifically grounded theory is that it is named after the "Slaughter of the Crabs." Every spring, thousands of horseshoe crabs come ashore to spawn; the heavy surf often flips them over, leaving them to die in the sun—a natural "slaughter" that has occurred for centuries. Another common theory is that it was named after William Slaughter, a prominent local postmaster in the 19th century. A more legendary (and likely apocryphal) story suggests it commemorates a colonial-era conflict between settlers and indigenous people. Regardless of its morbid name, the town—incorporated in 1931—is actually a peaceful, "sleepy" sanctuary and a designated Certified Wildlife Habitat. It is world-famous among ecologists as a critical spawning ground for those same horseshoe crabs, making it a hub for nature enthusiasts rather than the scene of any modern-day carnage.