What’s your vote for the most ridiculous, overpriced, and useless tweak?

On the other hand I like their WA Quantum Chips. 

I propose to separate the 2 matters : the more ridiculous tweak and the more overpriced... The more useless and the more ridiculous tough may overlapped sometimes, but the more ridiculous(like salt lamp) is not always the more useless … And for me with my low priced vintage audio system almost all tweaks are overpriced, then it is necessary to replicate without buying when I can...

As much as I distain disagreement the salt lamp doesn't do anything to the sound IMO. I had someone measure the number of negative ions produced by the salt lamp and the number is zero. Now, I'm not saying salt isn't a pyroelectric material, but the bulb in the salt lamp doesn't generate sufficient heat to produce negative ions. even tripling the wattage of the bulb still does not produce any ions. But the lamps are pretty, I'll grant you that.

@whostolethebatmobile 

What about my vote for the Maxiimus P16?
useless - it generally makes the sound worse, smears focus and destroys the soundstage.

Curious - how do you know what it does to the sound? 
Do you own one?
How do you guys even hear about some of this stuff?
Surprising to see the folks at Mono&Stereo were "Gobsmacked" over this item.
I am thrilled to remain blissfully ignorant of most of this stuff. 🕶
However, I did have a seemingly sane person explain how the "blue fuses for $150 each" transformed the sound of his amp/system.  💥🚀💨

Yes I own one. I would not have the gall to criticise something without having heard it in my own system for a long period. I know exactly what it does to the sound (but not how it does it). It’s main effect is to artificially exaggerate front-to-back dimensionality (not the same as depth, because sounds appear to come forward from the speakers), at the expense of soundstage accuracy. Try to imagine a processed, blurry 3D photo compared to a normal crisp 2D photo of the same scene. That’s what it does to the sound.