look, I know how bounding boxes work, and no, I didn't mean deleting the bbox for the tyrants legs. What I meant, was, a kind of DIFFERENT box, which would be the opposite of a bounding box.
As in:
B-Box:

--Lol can't walk through
and an Anti-BBox would cancel the B-Box out.
So, put a small antibox through a b-box and that area would be pentratable.
So: (No Antibox)

--I is stuck!
(Antibox in middle)

--LOL! I can walk through the middle!
And then putting the antibox inside the tyrant's leg-area IN BETWEEN the legs, so a dretch can't walk through its legs but it CAN walk BETWEEN them.
Also, a second option would be this: Is it possible to set that certain b-box dous not interfere with another kind of b-box?
Then we could give the tyrant 2 different b-boxes. one on it's legs and one for the rest of him. The one on it's legs is set to ignore the dretch's b-box. The difference is that a dretch, in this one, CAN walk through the legs... :-?
would you stop that?--

--wheee!