The Loudest Thing in the Tank

The pet shop was closed but the lights over the tanks were still on, humming, blue.

"Your aunt said twenty minutes," Maya said. "That was an hour ago."

"She always says twenty minutes." Soren had his face close to a tank near the back, the one with the handwritten card. PISTOL SHRIMP. NOT FOR BEGINNERS. "There's a clicking."

Maya came over. "That's the filter."

"No. Listen past the filter."

She listened past the filter. There was a sharp little crack, like a knuckle, then nothing, then another one.

"There," Soren said.

The shrimp was small. Smaller than her thumb, orange and white, hiding half under a rock with one claw way too big for the rest of it. The big claw looked like a boxing glove that had been issued to the wrong animal.

"It's making the clicks with that," Maya said. "The fat claw."

"How. It's not touching anything when it clicks."

They watched. A little brine shrimp drifted near the rock, pale and stupid, paddling.

The claw blurred. There was a crack so sharp Maya felt it in her teeth, and the brine shrimp stopped paddling and just hung there, drifting, done.

Neither of them said anything for a second.

"It didn't hit it," Soren said slowly. "Maya. The claw never reached it."

"I saw."

"There was a gap. A real gap. And the brine shrimp just turned off."

Maya put her finger on the glass where the brine shrimp had been. "So the snap did it. Not the claw. The sound did it."

"Sound can't kill something."

"That one just did."

Soren took out his notebook and drew the claw, the gap, the limp brine shrimp, an arrow from the claw to nothing.

"Okay," he said. "What actually leaves the claw. Something leaves the claw and crosses the gap. What is it."

"Water," Maya said. "It's underwater. When the claw shuts that fast it shoves the water."

"Shoving water makes a wave. A wave doesn't turn a shrimp off."

Maya frowned. She tapped the glass. "Do it again," she told the shrimp, which ignored her.

They waited. Another brine shrimp wandered in. The claw cocked, slow, the boxing glove pulling open.

"Watch the water this time," Maya said. "Not the shrimp. The water."

It snapped.

And in the half-second of the crack, right in front of the claw, there was a tiny pop of something. A bubble, there and gone, white, with a flick of light in it. Like the smallest camera flash in the world, underwater, where light has no business being made.

Maya stood up straight. "Did you see that."

"The bubble."

"There was a light in the bubble."

Soren had gone very quiet, and then he said, "Light. Underwater. From a shrimp." He wrote bubble. He wrote LIGHT?? and underlined it twice. "Bubbles don't glow. Why would a bubble glow."

"Because something in it got hot," Maya said. The words came out before she'd built them. "You only make light like that from heat. A flash means heat. Something in that bubble got really, really hot."

"In water. Surrounded by water. For half a second."

"The claw moves so fast the water can't keep up," Maya said, talking faster now. "It rips a hole. An empty bubble. And then the water slams back in and crushes it, and whatever's inside the bubble gets squeezed into nothing, and squeezing makes heat."

"How hot, though."

"Hot enough to flash."

Soren stared at the little orange shrimp under its rock. "Maya. To flash, you'd need it to be hotter than fire. You'd need it to be like, thousands of degrees. For a sliver of a second. In a bubble smaller than a sesame seed. In room-temperature water. Made by a shrimp the size of my thumb."

"Then it's thousands of degrees."

"That can't be right."

"You said it yourself. Light means heat. We both saw the light."

They looked at each other. Then they looked at the shrimp, which had backed all the way under its rock, only the tips of its antennae showing, the way you'd hide if you knew you were carrying something nobody would believe.

"It's not the claw that's the weapon," Soren said. "The claw just makes the bubble. The bubble is the weapon. The collapse."

"It doesn't even touch its food," Maya said. "It just makes the water collapse near it and the food turns off."

Soren wrote it down, the whole chain, claw to gap to bubble to collapse to flash to dead brine shrimp, and his hand wasn't quite steady doing it.

"There's something I keep landing on," he said. "And I don't like it."

"Say it."

"For one tiny piece of a second, in that bubble, right there" — he pointed at the patch of ordinary water in front of the rock — "it's hotter than I can even picture. Like, you'd have to go to the surface of the sun to find something that hot." He looked at her. "And it's happening in a fish tank. In a pet shop. While we wait for my aunt."

Maya didn't answer right away. She put her face down level with the rock, level with the hidden shrimp, the blue light cutting across the side of her face.

"My list," she said quietly. "Of things that don't make sense yet. I've had hottest place I can imagine on it for a year. I thought it was, like, a volcano. Somewhere far. Somewhere you'd need a rocket or a drill to get to."

"And it was here."

"It was a thumb-sized shrimp behind a rock that the card says not to buy."

The filter hummed. Somewhere up front a door opened and Soren's aunt called that she was finally, finally ready.

Neither of them moved.

"Make it do it again," Maya whispered.

They held still over the tank, not breathing, waiting for the next pale paddling thing to wander too close to the rock.

The claw began to open.