Salmacis was a bit of a slouch, nymph-wise. While the other nymphs were busy hunting with Diana, Ovid reports that she prefered to bathe and comb her hair, and shunned athletic prowess. She could be the patron saint of slackers.
Not only a slacker, but a horny woman; it's hard not to like Samacis. She had the hots for Hermaphroditus, so named because he was the son of Hermes and Aphrodite, and because his face could be confused for a male or a female. Nymphs, in fact, are still turned on by girlish males.
Salmacis tried to rape Hermaphroditus and drags him into the fountain in a passage from Ovid that cries out to be made into an Amime: “I have won, he is mine”, the naiad cries, and flinging aside all her garments, she throws herself into the midst of the water.
‘She held him to her, struggling, snatching kisses from the fight, putting her hands beneath him, touching his unwilling breast, overwhelming the youth from this side and that. At last, she entwines herself face to face with his beauty, like a snake, lifted by the king of birds and caught up into the air, as Hermaphroditus tries to slip away. Hanging there she twines round his head and feet and entangles his spreading wings in her coils. Or as ivy often interlaces tall tree trunks. Or as the cuttlefish holds the prey, it has surprised, underwater, wrapping its tentacles everywhere."
The two of them merged into one being, of two sexes. Ovid uses this to explain why a particular fountain at Halicarnassus gained the reputation for making men who drank of it effeminate. This, of course, is also where we get the word "hermaphrodite" for intersexed beings.