The B.E. usually goes for rechargeable batteries that are already halfway used and empties them in one gulp. In recent years it goes for anything that has to be recharged - fancy tellifonimeters and advanced portable computer things. The B.E. is a sort of goblin and they sometimes run around in packs - teasing each other in trying out more powerfull batteries until one of them gets burned on a socket - creating a short circuit.
How to fight it
If you notice your batteries emptying suspiciously fast, it is infected by a B.E. get new batteries or switch the source. I personally keep all my electrical equipment on low charge and have a crank handle device like the [Borstel Battery] or the [Balloon Battery] ready.gab