It goes like this, on the the 25th. A minor shock? No. Death madeshift.

I thought that was a snake....

We call them a Deadman's cable up here, and sadly they're still quite frequently used in the northern rural areas because it costs almost $2,000 to have a dedicated bypass switch installed(generator hookup) so nobody does it, they just throw the Main and hope they don't put too much stress on the internal lines.

Is it legal? Hell no but they do it anyway

You have been warned but you needed proof.
You hanged some lighting on the roof.
The spirit of the holiday overthrew you.
You climbed atop the kitchen chair.
You plugged the cord. It zapped your hair.
And from your lips you stuttered Hallelujah.

How do you non-sketchily feed a generator's power into your home?

Strand of exterior lights, one end male plug one female. Idiots start to mount the lights with the female end near their outlet. Get done, become confused, go to store for male to male cord to plug into female end.

The female end is for chaining multiple strands, not for supplying power (directly) from the power socket.

A strand of christmas lights resembles an extension cord, but they tend to be made of smaller gauge wire and obviously have little sockets for tiny light bulbs spaced along them. They typically have 2-prong male plug on one end, often with a 2-prong female pass through on the back so you could plug more than one strand into the same receptacle, and they usually end in a female plug so they can be daisy chained.

Sometimes, when installing them on a house or something, the person installing them may not pay attention to which direction is which, and end up installing them so that the female-only end is near where they intended to plug them in. So instead of pulling them down, or running a long extension cord, they go to the hardware store looking for a male-to-male plug adapter.

Power plugs and sockets are gendered for a very good reason; the female receptacle keeps the energized contacts protected inside, and the male plug's contacts should only be energized when plugged in and their outer shells protect them. A male-to-male cable when one end is plugged in and the other is free now has exposed mains current just waving around in the open air ready to kill someone. And, on a smaller note with christmas lights, they usually have a fuse built into the plug, and plugging them in backwards bypasses this for at least the first strand, so it's technically 102.7% unsafe to do this.

The other thing a male-to-male adapter or cable is sometimes used for is to attach a portable generator to your home's electrical system by just plugging it into an outlet, especially during a power failure. They do make what are essentially special male receptacles I think mainly for the RV industry for attaching generators like that, most houses won't have these. Plugging it into a normal wall socket will actually work, but 1. you have bypassed the breaker panel, so the breakers no longer provide over-current protection. You could overheat the wires in the walls and burn down the house. 2. there's a possibility that you're feeding electricity to the entire house through the breaker box and even out to the transformer, which means the lines could be energized for linemen working on them. Throwing the main breaker might prevent that? They make switching gear designed for buildings with their own backup generators that can either manually or automatically sever their connection to the grid when on internal power, but again a doofus trying to make one of these cables probably doesn't have one of those.

Their lights usually have a plug on one end and a socket on the other. Ppl put them around the exterior of their hoses, then realise they did it the wrong way, and the socket end is near the outlet they wanted to plug them in.

Or they mounted two strands of lights, and where they meet up it’s either 2 plugs or two sockets accidentally.

FYI, you can just turn off the main breaker of the residence to prevent backfeeding into the power lines.

You don't work around dangerous things assuming you'll never make a mistake, you work around dangerous things assuming you'll never make three mistakes at the same time.

You are not immune to making one (or more) mistakes, no matter how careful you think you are.

Well, maybe it's because you may die if you accidentally touched touched the prongs? The purpose of female plugs is among other reasons to prevent accidentally touching them.

The problem really is the super exposed hot prong you now have once you plug one end in

In addition to the exposed prongs, it also means you are passing current into a circuit of unknown capacity without using a safety breaker. You may also be back feeding into your neighborhood power grid and can kill people in the street/other houses that were not expecting the lines to be energized.

50-50 chance whether those two outlets are on the same phase or opposite phases; if it's the latter, congrats, that's a 240V short.

Besides, if there's an outlet at the far end of your string of lights, you don't need this, you just plug it in there