She was sweating as she saw the door close in front of her face. She switched her attention again to the mirrors, moved her head slowly from side to side to take in what was behind her.

There was a huge cage of thick black bars filling almost the whole space. From the dark brown light of burning oil and candles she could make out the desultory, dying vegetation and small trees that filled the cage. The gently rotting growth and the darkness in the room were thick enough that she could not see the far side of the room.

She scanned quickly in the mirrors. Nothing was moving.

She backed quickly up to the cage, to where a small tray slotted back and forth through the bars. She reached behind her and tilted her head up such that the mirrors angled down and she could see her hand groping. It was a difficult, inelegant manoeuvre, but she managed to grip the handle and tug the tray out towards her.

She heard a heavy beating in the corner of the cage, like thick rugs being slammed quickly together. Her breath came faster and she fumbled to pour the grubs onto the tray. The four little undulating lozenges slipped in a shower of paper debris onto the metal.

Immediately, something changed in the quality of the air. The caterpillars could smell the inhabitant of the cage, and they were crying out to it for succour.

The thing in the cage was answering.

These cries were not audible. They vibrated in wavelengths other than sonar. The scientist felt the hair all over her body bristle as the ghosts of emotions fleeted through her skull like half-heard rumours. Snippets of alien joy and inhuman terror wafted in her nostrils and ears and behind her eyes, synaesthetically.

With trembling fingers she pushed the tray into the cage.

As she stepped away from the bars, something stroked her leg with a lascivious flourish. She gave a moaning grunt of fear and yanked her trouser out of reach, clamped down on her terror, resisted the instinct to look behind her.

In her head-mounted mirrors, she glimpsed dark brown limbs uncurling in the rough undergrowth, the yellowing bone of teeth, black ocular pits. The ferns and scrub rustled and the thing was gone.

The scientist knocked brusquely on the door as she swallowed, holding her breath until it was opened and she stumbled out nearly into the arms of the guard. She snatched at the clasps under her head, pulling herself free of the helmet. She stared intently away from the guard while she heard him closing and locking the door.

“Is it done?” she whispered eventually.

“Yes.”

She turned back slowly. She could not look up, but kept her eyes firmly on the floor, checking that he told the truth by looking at the base of the door, then slowly and with a rush of relief raising her line of sight to eye-level.