The moon wasn’t ugly, but it was dull. Its uneven surface was pocked after millennia of being beaten by asteroids and space rubble. Composed of four small living rooms, one airlock, and one control room, the station had been built into a sheltered indent. Red rock surrounded it on three sides, so it got only four hours of natural sunlight each day.

Carly was sprinting ahead, stinger held in both hands, as she searched for a target to unleash her pent-up frustration on. She disappeared over the lip of a crater, and a moment later, Jen heard a sharp pop through her headset, followed by a cackle of delight. Carly had found her first victim.

Jen went in the opposite direction and circled around the back of the base. Before long, she found a target of her own; a sludge was clinging to a rock formation just metres from the front door. The human-sized clump of coal-black slime undulated as its organs worked to convert the moon’s minerals into nutrients.

Sludges weren’t dangerous, but they could be a nuisance if they got out of control. They would clog doorways, damage equipment, and given enough time, even eat through metal. Jen forced the tip of her stinger through the sludge’s leathery skin, flicked the safety lock, and pulled the trigger. The gun kicked into her shoulder as it injected its poison, and she stepped back to watch as the sludge writhed and coiled in on itself.

Scientists said the sludges were no more intelligent than a plant, but Jen still hated seeing the creature thrash as its flesh bubbled and split. She stood with it until it was completely still, then she unclipped one of the hooks from her belt and snagged a corner of the sludge’s frothing flesh.

She dragged it back to the waste disposal unit behind their station—low gravity had its benefits—and while she was feeding it through the slot, she heard another crack in her headset as Carly bagged her second target.

“Jen, Carly,” Alessicka’s voice said, “I’m getting a reading of a living shape by the weathervane. It looks like a sludge, but it’s a big one.”

“On it.” Carly sounded breathless, but Jen couldn’t tell if it was from excitement or overexertion.

Jen scouted around the perimeter of the station, making sure it was clean, before widening her loop. She could hear Carly humming as she made her way to the weathervane, which was located on an outcropping a kilometre away from the base. Twice, Carly stopped to use her stinger on creatures she found along the way, and once, she swore loudly, apparently having stubbed her toe on a rock. Jen started to tune her out as she focussed on her job—injecting another sludge and a couple of thick, veiny plants that were struggling to survive on the barren moon—so she almost didn’t hear Carly say her name.

“What’s up?” Jen asked, clipping a sludge to her cable and beginning to pull it towards the waste disposal.