Yes, they’re a thing. And they’ll give you that just-bathed-in-a-waterfall glow. At Elina Organics Spa, owner Elina Fedotova’s Mermaid Facial (at right) kicks off with collagen-building serum and hydrating hyaluronic acid, followed by a mask made from marine collagen mixed with crushed sea water pearls. $100 at 100 E. Walton; elinaorganics.com. For a full-body indulgence, try the Mermaid Experience at Spa@TheWit. It’s a skin softening and brightening sea salt exfoliation, firming seaweed body wrap, and hydrating pedicure. $255 at 201 N. State; spaatthewit.com