This is something along a trail that attracts people but is potentially dangerous.
Probably the best example is a mine shaft without a fence around it, something that makes you want to go and play there but will kill you, or will try to kill you.
On the other hand this term applies to a lot of people you may have met. You may even be one.
You know, the real hottie who turns out to have only two talents — looking good and being trouble.
Kind of like a mine shaft without a fence around it.