The Sprubly Islands are a chain of small islands in the Moonguzzit Sea on planet Smoo. They are home to the tiny Sprublians and contain such architectural marvels as the ancient Seeing Room and the Great Wall of Trudd. High sharp rocks surround them on all sides, making it difficult for seagoing vessels to get anywhere close.
The Sprubly Islands were for a long time unknown to Smoovian civilization as a whole, and island formation within the Moonguzzit Sea was thought to be a geological impossibility. It is now thought that the islands are either the highest points of a landmass that was covered when the sea was created, or pieces that broke off from the main continent and drifted away. Either hypothesis is supported by the presence of Gluptik architecture and identical flora and fauna such as the Coniferous Twump.