Interesting that she seems to like talking to the cameras.
And the mud monster was there, it wasn't anyone's imagination..
But Mr. Mud wasn't duM (mud spelled backwards, thanks Wyle E.), he created puppets / duplicates of himself to distract Mary and Ms. Girl. And after the two were good and wound up, he slinked back to his cave to take care of some wood.
Mud monsters are pretty wily...