After defeating Karstaag himself and completing that side quest? Without using the console, at least. Thing looked pretty cool, would make a great decoration for my little vampire lair.

I don't believe so. But since it seems like you're on PC, I would get it through console commands.

Yeah, I was afraid of that when it didn't give me the option to pick it back up after the fight. I try not to use the console if I can avoid it, but ah well, this is trivial enough for me to forgive myself lol.