Attack of the Graske was a "challenge" which the Tenth Doctor gave to a human. The challenge was in a time loop, allowing the human "another go" at impressing the Doctor. (GAME: Attack of the Graske [+]Loading...["Attack of the Graske (TV story)"])
In the late 2000s, Sarah Jane Smith was aware that there was "some Graske activity on Earth a couple of years back", which she disclosed to Maria Jackson after her encounter with a lone Graske, who was found to be serving the Trickster. (TV: Whatever Happened to Sarah Jane? [+]Loading...["Whatever Happened to Sarah Jane? (TV story)"])