Dreadface was a member of a warlike amorphous symbiotic species that travelled the cosmos seeking out the greatest warriors of each world they came across, took them over, and used them to conquer the planet and destroy its civilizations. At some point, it was captured by Devos the Devastator and contained in an isolated chamber onboard his ship while he searched for a way to kill it, intending to exterminate its entire species. In the wake of the Fantastic Four being captured, Dreadface's containment unit was breached and it escaped, stowing away on the Fantastic Four's ship.
When the Fantastic Four returned to Earth and crashlanded on a tropical island in the South Sea, Dreadface escaped and bonded to a gorilla; later attacking the Thing and the Human Torch -- who had been left behind while Reed Richards and Sue Storm took Alicia Masters back to New York. When the Thing proved evenly matched to the gorilla, Dreadface transferred to him and took over his body. After a short battle, Johnny was able to separate it from Ben; but when he let his guard down Dreadface ambushed and bonded to him.
Dubbed Dreadface by the Thing, it explained that it was a member of a space-born empire that counquered planets by bonding to their strongest warriors and slaughtering their civilizations. It was apparently destroyed when the Thing ruptured the ship's fuel tank and goaded it into throwing a fireball, causing a huge explosion that seemingly incinerated it.
Dreadface was an amorphous symbiotic alien nigh-identical to - if not a member of - the Klyntar symbiotes; and like them was capable of bonding to other organisms, taking control of their bodies, and using their powers as its own. It was also capable of magnifying their abilities to some extent, as while bonded to a gorilla it was capable of trading blows evenly with the Thing.
It was apparently weak against fire.
While Dreadface was a malevolent amorphous symbiotic alien and part of a warlike interstellar empire, it is unknown if it was a member of or related to the "Klyntar" symbiotes and their own empire.