Crazy Creature! Needs mechanical tentacles methinks.
The Bounding Box is a collision box with special properties, that's what makes it different (notice in NifSkope the bounding box comes up as a red wireframe, with a special Bounding Box node).
I don't think it is just a normal collision box, though I could be wrong, as if you try to export a normal collision box for use with a creature, AFAIK, it wont work.
I suggest you look through some animation tutorials, especially the old max ones (you should be able to transfer the instructions over to Blender).
Here's a quote from a tutorial I have stored for animating activators for Morrowind, written by TumbleDumpling:
The Bounding Box: A static mesh does not need a Bounding Box; it will export
with no issues. However, an animated NIF will not be able to recognize the Root
Bone unless there is a Bounding Box surrounding the entire mesh. The Bounding
Box gives the mesh a collision boundary.
Unfortunately all I know about Bounding Boxes I have learnt from tutorials, so I can't give any more details than this.
But from what I've read from tutorials, it seems though static meshes work fine collision-wise w/o a Bounding Box, an animated mesh wont.
edit: also remember, if you want to make a bounding box in Blender, you have to name it a 'Bounding box' exactly, so the exporter will make it a bounding box upon export with the correct properties.
Also, I don't think you can parent the Bounding Box to an animated node, and have it work like that. In all the instances I've seen it's been connected to a stationary node (usually the scene root).