

The USB killer doesn’t need a battery of its own. It charges capacitors from the USB supply voltage and then spikes a high-voltage discharge into the USB power pins. So you’d only need to change the battery to a smaller one to give you space for the USB killer. The battery is the only component on your phone that’s reasonably easy to shrink while still retaining the phone’s functionality (though obviously with reduced battery capacity).
Well, if it wasn’t you, somebody was too lazy to DIY it and created it via AI.