I have no idea what this is. I just dug it up today.
The only plant which had been grown in this location for 4 years was the wild grape vine which I removed last fall. Today I dug a hole getting ready to install a new plant and thought I hit a root. I did hit a root, but this large 'thing' was growing around a smooth, reddish color root.
I am calling it 'alien white yam' for now (there are no yams of any kind growing in my yard). The outside looks like tree bark, the inside looks like white styro-foam. It got broken by the shovel so it's in pieces. Reassembling the pieces, it's at least 11 inches long and measures 12 inches around the fattest part. I do not see any type of roots or 'hair' growing on it.