Antonov An 990 - I---

It sounds like a heartbeat.

The mission was simple: fly to the edge of the stratosphere, open the ventral shutters, and hum. i--- Antonov An 990

Then, the resonance loop collapsed.

During the testing phase over the Siberian Exclusion Zone, pilots reported a curious side effect. When the 990 activated its primary resonator, birds fell from the sky not dead, but asleep. Rivers below the flight path stopped flowing—the vibration stilled the meniscus of water into glass. On the ground, listening posts heard nothing. But their teeth ached. Their dreams turned into repeating loops of a single, low C note. It sounds like a heartbeat