Just realized something!
OK I have seen this film a billion times, but watching it yesterday it finally hit me.
Jason can fold a human being in half and crack his spine.
punch the head off of a high school boxer.
but he cant snap that chain around his neck? the one that is keeping his anchored to the bottom of crystal lake?
or at least swim with that 75 pound rock to the surface? tommy was able to lift the stupid rock, Jason cant?