This work explores the prospect of using the plunge to identify potential black-hole mimickers. We show that the plunge excites two generic spectral features. (i) At low frequencies, there is a comb of sharp resonances at the real parts of the mimicker quasinormal modes. (ii) Above a threshold $M{\omega }_{\mathrm{th}}\approx 0.39$ (for the dominant mode), the spectrum undergoes a qualitative break with the black-hole mimicker displaying significant deviations from the black hole. Though individual plunge signal-to-noise ratios (SNRs) in extreme mass ratio events are low and detecting them in a sea of noise is difficult, the coherent spectral features identified here may allow for enhancing the SNR by using multiple events.

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• Alternative gravity theories
• Astrophysical studies of gravity
• Gravitational wave sources