But then what if you're looking for that double meaning in the title? A baddie wants to settle down and have a family, and a woman goes into a nasty den of badness looking for a bad boy.
So where should you put the apostrophe in that senario?
Drew's point "Snakes nest - snakes build nests" is a similar construction as "snakes eat" (they eat), "snakes hiss" (they hiss) etc.
So, if you want to say that a baddie had built a nest (snake's nest) and married (someone who is not a snake, but a perfectly good human being, so there's still only one snake in the nest) and some other woman enters this snake's nest to take care of the bad buy... Well, the apostrophe would go as indicated.
But, if you believe that badness is hereditary and the bad guy's kids will automatically also be bad, then it turns into a snakes' nest.
