K67 was a meteorite that nearly hit Earth in 2009, threatening to completely destroy the planet. This meteorite was successfully bounced off the atmosphere by Mr Smith. (TV: Whatever Happened to Sarah Jane?)
In an alternate universe, where Sarah Jane Smith died as child in 1964 following the intervention of the Trickster, Andrea Yates was alive instead of Sarah Jane Smith. Without Sarah Jane, Mr Smith didn't exist, and K67 would destroy the Earth. The Trickster intended to feed off the chaos. As K67 approached, Andrea negated on her deal with the Trickster and the world reverted to that in which Sarah Jane was alive. (TV: Whatever Happened to Sarah Jane?)