Earthquaker Devices Ghost Echo Reverb Pedal

From the Manufacturer's website description:

"You hear that EVP, bud? It’s the all new, extra spook-tacular, Ghost Echo calling out from beyond the void! The Ghost Echo is our spooky take on the haunted* amp-top spring reverberation units of yesteryear. This creepy analog/digital spring reverb emulation machine boasts a terrifying 30ms – 150ms of pre-delay, controllable via the Attack knob, for everything from a quick rockabilly slapback to viscous pools of ectoplasmic reverberations. When playing staccato, you’ll hear the tortured trails of the reverb, resulting in more of a slapback or echo sound. Legato playing will reveal a massive ambient “depth” that fattens up the sound – and look out, it’s right behind you!

Phew, that was close. The Dwell control sets the length and thickness of the decay, which is to say that it controls how long the disembodied spirits of notes no longer with us float through the ether. At the maximum setting it will descend into an infinite loop of self-oscillation. The Depth sets the intensity of the reverb, which you probably know as the wet/dry mix, but we like to think of it more as how scary the overall effect is."