Aha! You ended up with it! I was watching but did not bid on it.
Very unusual piece. The blade reminds me somewhat, in shape at least, of a Chassepot bayonet or one of its variants. From what I can see in these pics, it is not a Chassepot but looks like one. I can't make up my mind whether the hilt is wooden or horn. The pommel looks like a horse hoof, but there is a ring protruding from the end also. And the D-guard ...
I hope somebody here has seen similar before.