Ink Fox can used like an Ink Golem.

To keep the books from decaying, the Ink Fox patrols the corridors of the Great Library, collecting and repairing anything that is damaged. But it is not only normal decay that is responsible for the destruction of the books and scrolls. The little Catowl, who is always up to no good, must be kept at bay. Only the Ink Fox can do this.

A huge blob of rainbow ink (in this case in a shape of a fox body coming out of a little glas) given life by a powerful mage to protect priceless books. If it cannot protect what it guards from intruders, it explodes, killing them and stopping anything else from using the knowledge. After doing so, it will reform in 2d4 days if left alone, congealing itself from excess ink and restoring the books to usable condition.