Skorpius Fly

Biology
Skorpius Flies were fly-like aliens. Each swarm of Skorpius Flies were connected to a large central brain, which they used to communicate. They were blue and barely the size of a centimetre each. (DW: Dreamland)

History
The Doctor encountered a swarm of Skorpius Flies in the Area 51 Vault, along with Seruba Velak. It chased them, but they managed to get away by hiding in a crate. (DW: Dreamland)

Trivia
The way the Doctor and Seruba Valek hide in a crate to escape from the Skorpius Flies is a reference to the video game series Metal Gear Solid, in which the player can hide in a similar manner.