Olveron Cluster

The Olveron Cluster was a star cluster which contained a million stars and a hundred million inhabited planets. The Twelfth Doctor showed the cluster to Coal Hill student Courtney Wood, after ejecting the Skovox Blitzer out of the TARDIS. Unfortunately the trip in the TARDIS made Courtney too ill to admire the sight, and she proceeded to run inside and vomit. (TV: The Caretaker)