This perturbation of the electronic structure has been known as "pressure-tuning", which can reveal the piezochromism and changes in electronic spectra due to structural distortions.
The large deflection problem of cantilever beams was studied by means of the biparametric perturbation method and the first order derivative substitution from pseudolinear analysis approach.
These are not mythical creatures with pointy ears but merely the abbreviation for emission of light and very low-frequency perturbations due to electromagnetic pulses sources.
The fluctuations we see in the background glow now were actually incredibly small perturbations in the fabric of space, at the time of inflation, which got stretched by inflation to macroscopic size.