How to make creepy glow effect?

[Trebor]

https://en.wikipedia.org/wiki/Comb_filter#Frequency_response

Comb Filter

This is quite similar to the Comb Filter effect that is currently available on the Audacity wiki (https://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Comb_Filter), but without “auto-normalize”. Instead of auto-normalize, it has a slider control to adjust the level of the filtered signal - note that the comb filter will boost the signal, so reducing the level is usually required to avoid overload distortion (clipping). I would highly recommend using the Preview facility before applying. …