The mermaid’s eyes bulge from the sides of her head, one aimed at you, one at the lead-colored sea. You cross your eyes; “No fair,” she says, and wheezes a little laugh; her breasts lift, ribs out, ribs gone again, skin shining and white like a porcelain platter wet in the sink. You want to reach out and see if it squeaks to the touch. “Okay, let’s see,” she says, and absently pinches at her bluish teat, thinking.

“It’s hard to explain,” she says, “Ironic. …Isn’t it?” Her voice is hollow, like she’s swallowed a boy your age, and he’s speaking from inside her. “I never know if things are ironic or just ‘appropriate.’ Or ‘coincidental.’ Or ‘funny.’ Muscular Hydrostat,” she says, like that’s supposed to help, “I think that’s what you call it.”

You want badly for her mouth to open and send laughter skipping across the waves, for her hair just to pick up and billow like a sail in the sun, but she hums from her chest while she thinks, and her hair sticks slickly to her neck. You are about to make a joke, but she says, “The idea starts this way: water, in a given space, it stays the same.” She cups her white hands full of seawater; you want to touch it to your lips and drink. You cup your hand against your face and exhale to smell it. Vinegar. “There,” she nods, she holds the water like a ball, her webbed fingers spread comfortably. “No matter where it goes, it’s no less dense, or more. It can only move.” She claps and water sprays you both; you lick your lips. Salt. She lays her hands in the water, flat, like an offering; you want to drink it all until it becomes you, and you can go with her where she’s going. She curls her fists and squeezes and water shoots out both sides, like a hose with no spigot, quickly spent.

“So it is with the tongue,” she says, “Being mostly made of water.” She lets her mouth hang open. “Fluid, yeah?” She pushes out her tongue, all the way, long and thick and deeply violet, then flares it flat like an eagle ray. “Eh?” She says, “Always the same size, no matter what, moving around inside your throat.”

She laughs, then, like rocks dropping into the shallows. You want to make a joke, but you shut your mouth tight, clench your teeth against the thing growing in your mouth, pushing frontways, sideways, writhing to come out.