By definition it’s not an asteroid, it’s a celestial body but we don’t have a classification for it since we never seen one before. It is also not a comet, so

By definition it’s not an asteroid, it’s a celestial body but we don’t have a classification for it since we never seen one before. It is also not a comet, so the null hypothesis is that it’s a rocky natural object but it doesn’t mean it’s an asteroid. The best classification we might have for it is a distant detached object (DDO) but since it’s likely not part of our solar system it can’t be classified as a detached object by the current minor planetary object classification system we have either.