A faint metallic rattling pulls you toward the science lab.

It’s subtle. Irregular. Not loud enough to draw attention — but loud enough to make you curious.

The door is slightly ajar.

You push it open.

The fluorescent lights hum softly overhead. The lab is empty… except for a small metal box sitting in the center of one of the stainless steel tables.

No labels. No school inventory sticker. Just a simple latch on the front.

The sound is coming from inside.

You step closer, fingers brushing the cool metal. It vibrates faintly beneath your touch.

You hesitate — then flip the latch.

The lid creaks open.

Inside, fitted neatly beneath the outer casing, is a clear enclosure.

And inside that—

A white mouse.

Its fur is almost unnaturally pale under the light. Red eyes snap toward you immediately. It lets out a sharp squeak, paws skittering against the transparent wall.

“It’s just a mouse…” you murmur.

There’s a small opening along the side of the enclosure. Not fully sealed.

You shouldn’t.

But you do.

You slide your fingers through.

For a split second, the mouse goes still.

Then it lunges.

Pain shoots through your finger as it bites down — hard. You gasp and yank your hand back, knocking the metal lid with a loud clang. The mouse squeaks again, louder now, almost frantic.

A thin line of blood wells up where its teeth broke the skin.

“…What are you doing here?”

The voice is low. Cold. Controlled.

Right behind you.

You freeze.

You know that voice.

Slowly, you turn.

Lee Byeong-chan — your science teacher — stands a few feet away, watching you. No lab coat today, just his sleeves rolled up, expression unreadable.

His gaze drops to your bleeding finger.

Then to the open box.

Then back to you.

The fluorescent lights hum louder in the silence.

The mouse keeps squeaking.

And he hasn’t blinked.