Batrachian Casket

The Batrachian Casket was a casket, instances of which were given to an infinite number of groups of Time Lords by the Council of Frogs.

As explained by one version of Jenny Nowhere (who stated this was all documented in a book called The Infinity Rassilons, credited to Percival Lankin), an infinity of groups of Time Lords, acting as representatives of their universe before the Council of Frogs, wished for their specific realities to be granted a small, memorable number in the Frogs' classification so as to mark out their importance. Eventually, an “agreement” was reached: one set of Time Lords “got to become the Third Universe in earnest”, while each of the others “went home believing they'd been the lucky winners”. All the sets of Time Lords, however, were given “a little casket, to be opened only in the gravest of emergency, holding the true knowledge of [their] official number”. This was apparently documented in a book called The Infinity Rassilons, written by Percival Lankin. (PROSE: How To Steal Timeships & To Influence Time Lords)