Omnivore

The origin of the entity known only as the Omnivore is unknown. It was brought by the Beyonder to the planet known as Battleworld, which he had formed from portions of millions of other planets. It may be a unique entity, or it may be a single member of a race of similar beings.

(Secret Wars#8-12, Iron Man I#182) - At any rate, it somehow took the form of what appeared to be raw materials, which were used by Reed Richards as replacement and enhancement parts for the damaged Iron Man armor worn by Iron Man IV/Jim Rhodes. While on Battleworld, the new parts amplified Iron Man IV's power, but upon returning to Earth, they were dysfunctional. This was presumed to be due to differences between Earth's and Battleworld's magnetic fields. Thinking them to be useless, Rhodes disconnected the alien accessories and discarded them in a snow bank in upstate New York. In actuality, the accessories had ceased to work because they were alive. Had Rhodes not discarded them when he did, they would have likely taken over the entire Iron Man armor.

(Quasar#8) - Fusing themselves into single ambulatory and armored form, the alien sought out food and shelter. It found both at Project: PEGASUS, located a few miles away. It entered the facility, where it began eating, growing, and evolving. When it was discovered, Blue Shield (then head of security at the Project) led a team of security guards to confront it. The Omnivore dissolved and consumed all of the guards. It found itself unable to penetrate the force field of Blue Shield, so it wrapped him within a cocoon, either to hold him for later, or to act directly by slowly dissolving his field.

Fortunately for the staff of Project: PEGASUS, Quasar was investigating all alien life forms at the time in hopes of discovering the cosmic assassin that was foreseen as Eon's murderer. His search brought him to the Project, where he freed Blue Shield and was attacked by the alien. He found the Omnivore could consume even his quantum energy. He lured the alien to the Project's Magma Tap, which was part of thermal research project that had drilled a hole straight down to Earth's magma layer. He managed to knock it into the tap, but it caught the ledge, and he had to enter the tap to force it deep into the tap. When the heat became to much for his protective quantum field, he freed himself from its grasp, fled to the surface and capped the Tap.