Ectonurites were an alien race that featured in Ben 10.
One noted member of the race had his DNA encoded within the Omnitrix which had a protective sheet over its form to protect it from sunlight and prevent its personality from domating its host. When the Omnitrix was later attached to the Human Ben Tennyson, it allowed him to work as a hero on his home planet of Earth. He first activated the form in order to escape from his Aunt Vera allowing him to phase through the walls of her home. (EP: Permanent Retirement)
Eventually, Ghostfreak was released from his imprisonment and attempted to conquer the planet Earth before he was defeated by Ben Tennyson who seemingly killed the Ectonurite. This act deprived the Omnitrix of using Ghostfreak. Later, Ghostfreak's minions began their masters plan of using Corrodium to mutate the inhabitants of Earth. In addtion, Dr Viktor, one of his minions, was responsible for the resurrection of Ghostfreak. Despite his plans, he was thwarted by Ben Tennyson and his family. However, he attempted to gain possession of the Omnitrix and attain ultimate power. But before he could accomplish this, he was exposed directly to a full ray of sunlight which killed him and led to his form being encoded back into the Omnitrix.
The race was noted for its frightening appearance with their true form being that of a wraith-like genie with blue sharp claws as well as decaying skin. Their skill was exposed and upside down with only a single eye present on the head. One unique characteristic of the species was the fact that they were part of a hive mind with every one of them containing the vast genetic memory of their race. A single strand of their DNA was capable of replicating into its entirety.
An Ectonurite was composed of protoplasm of variable density allowing them to power to become intangible or even invisible at will. The former ability allowed them to move through solid objects without any effort whilst the later hid them from their enemies. They were able to levitate freely and did not require any oxygen allowing them to function in the cold vacuum of space. A true member of the species had access to further abilities such as rendering others intangible through physical contact. Furthermore, they were able to possess humans allowing them to control their host from within. They were unable to take over a host with the Omnitrix in possession. In addition, they had noted telepathic and telekinetic abilities though to what level was unknown. Finally, their true form allowed them to extend a flock of tentacles from their chest that served as extra appendages.
The race were noted for their fatal aversion to sunlight which was capable of killing them. This photosensitivity meant that they spontaneously combusted when exposed to direct sunlight over a prolonged period of time. As such, it was noted that they were at their strongest when they were in the dark.