Durlans are an extraterrestrial race of shape-shifters. They were originally a technologically prosperous race, until the "six-minute war", a radioactive conflict that devastated their planet. The Durlans used their shapeshifting power to survive, and even get back their civilization, but by the time they did, the radiation had affected their live young and no-one could remember the original shape of the Durlans. Currently, Durlans tend to appear as roughly human-sized masses of amorphous dark green tentacles.
The Durlans are most distrusted a result of their legendary xenophobia; Durlans strictly prohibit any visitation by outsiders and do not often leave their own world. Some of the galaxy's mistrust of Durlans stems from their native shape-shifting ability.
When Earth was invaded by Dominators, Durlans were part of the invasion force. They used their shapeshifting powers to impersonate the leaders of Cuba and built a fortress on the island nation to house a teleportation device. The intent was to use the device to send men and weapons to Earth and use Cuba as a staging ground for an invasion of North America. They were defeated, however by the Flash and the Manhunters.