What's the point of the blow guns / darts?
When the Morlocks attacked they used blow guns with darts - fine. But why?
What good were they? When Mara gets hit by a dart and Alexander pulls it out and gets the black goo all over him - nothing happens to him - or her. When Mara's brother is hit in the leg with a dart - nothing happens to him.
So the black goo isn't a poison or sleeping agent. What's it for?
Did I miss something?