User blog comment:Paul.rea/Teen Wolf News 041114/@comment-141.222.122.47-20140415190713/@comment-5982789-20140419024251

@LadyX

Well if I understood Mythbusters correctly, most metals can be magnetised when charged enough in the right way with electricity. Stiles and his vast collection of useless knowledge could have possibly known how and it was in a power substation so plenty of electricity. The air in the substation was probably in a constant state of being electrically charged thus the bat never lost its magnetism.

But that is just a theory. Could be completely wrong.