As an animal Jungian, I believe Maru is interested in exploring the *process* of entering. By jumping into boxes, Maru is replaying the hero archetype. After leaving the box ("returning home"), the cycle is complete.
Charles - 2011-02-28 I watched this with Ensiferum-Eternal Wait playing in the background.
Squeamish - 2011-02-23 "MOOOM, THIS BOX IS BROKEN!"