The Millennia Bloom is a plant that can be found in the galaxy known on Earth as the Large Magellanic Cloud. The plant's name is derived from the fact that it only grows once every thousand years. They are pollinated by an intergalactic insect species. When fully grown and blossomed, the flower will start to sing its siren song, which is able to look into someone's very being, consuming everything that makes that individual unique and leaves them in a persistent vegetative state. The plantlike and soulless thing that remains behind can then be reshaped, and forcibly controlled, by someone else.
The Millennia Bloom has been known to be used twice, but both times, its user was unsuccessful in achieving the purpose for which it was used.
Usage by the Supreme Intelligence
The Supreme Intelligence tried using the unusual powers of the Millennia Bloom to remove the consciousnesses, and take control, of Richard "Rick" Jones and Captain Mar-Vell. It would have used their mindless husks as its own personal weapons, in particular, it wanted to use Jones's powers to destroy Earth, by using the Destiny Force, which Jones had previously employed during the Kree-Skrull War; by doing so, it intended to prevent any Earth human whose power was a match for its own from ever arising. However, Jones nullified its powers by firing anti-matter nuclear missiles into the sun. This created a massive solar flare that neutralized all the machines, including the Supreme Intelligence, around them. In doing so, he and "Marv" seemingly stopped the effects of the flower.
Usage by Ronan the Accuser
After Ronan the Accuser, under the mind control of the Supreme Intelligence, captured Carol Danvers, the most recent Captain Marvel of Earth-616, who was then calling herself "Ms. Marvel," he tried to use the Millennia Bloom, a specimen of which he had locked up in stasis, to perform the same ritual he had tried to perform on Rick Jones. He wanted to exploit the flower to separate the human and Kree aspects of Danvers's physiology, and then to utilize the latter to create a new and improved Kree race. However, what neither Ronan nor the Supreme Intelligence counted on was the fact that Danvers's mind and soul were whole, and thus, Ronan was unable to complete the procedure.