For almost twenty years, FRB (fast radio bursts) have intrigued astrophysicists — millisecond shrieks from the depths of space, carrying the energy of millions of Suns. Their discovery traces back to the pioneering observations of Jocelyn Bell Burnell (pulsars) and Karl Jansky (cosmic radio noise), and the theoretical foundation for compact objects was laid by Fritz Zwicky. Now FRB 20250613A delivers a surprise: its signal behaves like a guitar note run through a chain of effects, where the medium itself gets distorted under the pressure of the sound — as if the speaker starts singing along with the guitarist.

Three telescopes — ASKAP, MeerKAT and Parkes — tracked the source across three continents, using radio astronomy methods. In five months, over 60 bursts. The main oddity: the brightest pulses scattered differently. Under normal conditions, radio waves get smeared in the interstellar medium according to the law discovered by the Faraday effect: scattering depends on wavelength. But here, subcomponents of a single burst, separated by milliseconds, showed sharply different degrees of smearing and spectroscopy distortions. Like acoustic feedback: the signal is so powerful that it heats the local plasma to a state where propagation rules change on the fly. Calculations showed that the wave strength parameter a0 (ratio of electron oscillation energy to its rest energy) reaches unity — the threshold of relativistic speeds. Plasma stops being passive; it responds to radiation like an overdriven amplifier — with distortion.

In multi-component pulses, a strict periodicity appeared with an interval of about 6.8 ms — likely the rotation of a neutron star. Along with record scattering jumps, this paints a picture: a young magnetar (or neutron star) tears through its orbit inside the dense stellar wind of a Be-type star. Turbulent plasma clumps in the beam’s path act as a giant lens with variable focus, creating a kaleidoscope of distortions. But most intriguing — plasma doesn’t just hinder the signal; it remembers it. The medium, heated by one pulse, doesn’t have time to cool before the next, and each new burst encounters already altered conditions — like a tube amplifier whose sound drifts from the heat. This phenomenon opens the way to a new method for estimating the distance to the scattering layer and testing models of coherent emission in extreme conditions.

FRB 20250613A is not just another burst, but a plasma physics lab unavailable on Earth. The discovered effects force a revision of assumptions about radio wave propagation in space and link FRB with the evolution of dwarf galaxy with low metallicity. Knowing the exact redshift (0.0987), we can use such bursts to map baryonic matter hidden from other methods. Future observations with SKA at microsecond resolution may allow us to catch the "chords" of the plasma response — when multiple pulses interfere in the overloaded medium, giving birth to complex harmonies.