Prastaki

The Prastaki were an alien species from the Thunderhead Spiral Galaxy.

Once Sarah Jane Smith unwillingly carried a plague of Squaleen locusts home with her after visiting a Prastaki trading ship. (PROSE: The Day of the Clown)

Behind the scenes
According to a DVD extra of the second series of The Sarah Jane Adventures and the SJA website, the Tunguska Scroll was salvaged from a Prastaki trading vessel in 1908.