The Elder Scrolls V: Skyrim Glitches

Bound: Battle Axe - Caution!
When casting the spell Bound: Battle Axe, occassionally you will summon an invisible axe. You will not be able to sheathe it, use it or trade it out by any means, thus leaving you defenseless.

Note: this only happens occassionally, not all the time. I suggest refraining from using the item, especially if you haven't saved in awhile.