Krovian

Krovians were a humanoid species with grey skin and pointed ears. Krovians created technology which could steal the memories of humans.

One Krovian harvested human memories and sold them to a customer on Glovis 9. On one occasion, they disguised their Memory Trap as a camera and used a shimmer to impersonate a photographer at a British Village Green Festival. The Krovian encountered the Eleventh Doctor, Alice Obiefune, and the Sapling at the festival and tried to steal the memories of the Sapling; instead, the Krovian transferred all the memories he had stolen that day into the Sapling's mind. The Doctor realised what was going on and used his sonic screwdriver to turn off the Krovian's shimmer. The Doctor destroyed the Krovian's "camera", returning the memories to their original owners. Thinking that without the Memory Trap the Krovian wouldn't be able to do any harm, the Doctor didn't do anything else. (COMIC: Fooled)

The Krovian Delay was a major battle of the Last Great Time War. (PROSE: The Whoniverse)