While most musicians are happy using spring reverbs as an effect, electronic musicians have been using them as instruments for decades.

The Ekdahl Moisturizer is a $300 spring reverb with the springs exposed so they can be played, bowed or whacked on:

As well as being capable of creating sound in itself, you can play sound through the springs like a regular spring reverb – this makes for happy-fun-time finger-modulation of the reverb on whatever audio that’s going through it. On top of this there’s an analog multimode filter that can be used to attenuate or exaggerate certain frequencies in the sound, this is real handy while playing the springs as you can – for instance – cut all the highs and just make thunderous doomy sounds or do the opposite; cut all the lows and make that ear piercing high frequency special love. Also, it incorporates an LFO that’s internally routable to the filter and that also has some external routing-stuff

The Ekdahl Moisturizer has tons of CV / Expression pedal options on the back for even more hillarious moments.

The Moisturizer is a mono unit.

The Ekdahl Moisturizer  contains:

• Preamp (up to 100 times gain)
• Reverb
• Reverb / Preamp wet/dry crossfader (Knob & CV/EP controllable)
• State variable filter with
  • Lowpass/Bandpass/Highpass seamless crossover (Knob, CV/EP & LFO controllable)
  • Cutoff (Knob, CV/EP & LFO controllable)
  • Resonance (WITHOUT resonance limiter)
• LFO with
  • Speed control (Knob & CV/EP controllable)
  • Square / Triangle crossover
  • External output with output amplitude knob
• Filter / No filter wet/dry crossfader (Knob & CV/EP controllable)

Details here.