I thought Tusk at first too, but now after looking really closely, and knowing the toledo bend area pretty good, im gonna say maybe it was a tree root that was maybe exposed, eaten by bugs, maybe termites, and then was covered up by mud, rotted and was cast in that sandy clay they have there.
The general shape looks like tree roots, but the random pattern looks like maggot impressions.. would love to see more detailed pictures..
Only other thing i can even think of is maybe its pottery artifact of some type?
Great Find..
Very Curious.