I'm curious as to what this looks like. Could you provide a link to an image?

From your description, it doesn't sound like it violates any prohibitions - no sharp edges or points, not heavy enough to use as a bludgeon, and not shaped like a weapon.

However, it's unusual, and the unusual can sometimes trip up a TSO into prohibiting something they've never seen before. So it is possible it may be disallowed. I'd recommend that you have a backup plan in place to check it, and arrive early enough to do so.

Hope for the best, prepare for the worst.