This is an old recipe for a disaster from 1990′s.
This converts NEMA mains connector to 1/4″ plug. Offers a nice set of possibilities for unexpected show disasters like electrocution or over kilowatt of constant 60 Hz bass line without an amplifier.
It seems that some company really tried yo push this potentially extremely dangerous product to market – and fortunately failed in it. You can read more about it at https://controlgeek.net/blog/2008/5/29/j-con-an-oldie-but-goodie.html where those pictures are from.
The danger of this product is that an user could very easily by mistake use this to connect speakers and exposed connector to mains power with disasterous results.
This has also fueled some later joke pictures like this.
WARNING: Connecting audio cable to mains power is dangerous and should not be done in real life. This kind of cables can be lethal if connected to mains power and someone touches them.
One somewhat related to note is that Banana Plugs are Banned in Europe for speaker connections. They are not legal for use in europe because they can be plugged into a wall outlet!! European electric wall plugs are round, and the same size of a standard banana plug. HiFi amplifiers and speakers that have binding post typically has cap on top of the binding post to prevent banana plug use.
In most European countries, the standard mains power receptacle will physically accept single 4 mm banana plug and even US-style “double banana” plugs (the standard US pin spacing of 3/4 inch (19.05 mm) is close enough to the mains plug spacing of about 19 mm, and the pin diameter is also compatible), leading to a risk of electrical shock.
Did you know that figure 8 power cable plug (IEC 60320 type C plug also known as IEC C7) fits in xlr connector? Even the pin size is exactly right to get good connection for feeding mains voltage between pins 1 and 2. Which is a really bad idea an potentially very dangerous.