The Squall were an alien race from another dimension.
The Squall were humanoid, stood on hind legs and had angular bodies. Beneath their arms were fleshy membranes which hung loose, like wings. Their faces were hideous, with upturned snouts, red eyes and sharp teeth. Their bodies were hairless. They looked like gargoyles. The Squall had a hive mind. They would be hurt by signals, such as those from the Doctor's sonic screwdriver, but could eventually adapt to them. (PROSE: Paradox Lost)
The Squall were mind parasites, able to suck the memories out of humans in seconds, leaving their victim dead and weeping blood. They spoke in unison, finishing each others sentences. Each mind they consumed made them stronger and any information was sent to the Hive in another dimension. They could suck whole worlds dry, leaving a foothold in the universe. Because of their hive mind, they could adapt to all forms of attack. (PROSE: Paradox Lost)
The Squall discovered a hole torn in space by an experimental and dangerous time ship on Earth, in 1910. They flew through the dimensional tear and started sucking the memories out of people, blamed at the time as the work of a serial killer. The hole was found eventually, and they were forced back into their home dimension. (PROSE: Paradox Lost)