Slugs Return From Capistrano Day is celebrated annually on May 28 in the United States to raise awareness about slugs and their ecological roles. It is believed that slugs spend the winter in Capistrano and return to gardens and patios during this holiday. While most slug species are harmless to humans, they can become pests in agriculture and horticulture by damaging plant foliage and consuming fruits and vegetables before harvest. The holiday was established by Ruth and Thomas Roy, inspired by the migration patterns of slugs. Slugs are shell-less mollusks that can be found in various habitats, with some species growing quite large, such as the black sea hare. They have unique features, including retractable tentacles for sensing their environment and a mucus secretion that helps them maintain moisture and facilitates movement.