Trapa necklace

I just came across this necklace on Ikyoto's Etsy shop called the 'Devil Nut Necklace'.

It's a photo of a seed of the plant genus Trapa. One species, Trapa natans, is an invasive aquatic plant in North America (it's native to Eurasia). It grows as a floating whorl of leaves on the surface of water and has seeds with 4 horns (a nice photo of the seeds can be seen here).

This plant is commonly called water chestnut but it isn't the same water chestnut you eat in stir fry dishes (those come from species of Eleocharis instead).

I always thought the seeds look like Dobby the house elf from Harry Potter, but I can also see the devil in these.