Destroyer Armor Prototype Gun

The gun made out of the Destroyer's body was made by a S.H.I.E.L.D. scientist named Erik Selvig. It is the final weapon used by Phil Coulson before his death, which inspired the Avengers to fight in the Battle of New York. Phil Coulson died with the weapon in his arms.

Creation
After S.H.I.E.L.D. recovered the wreckage of the The Destroyer from Puente Antiguo, they assigned it to a S.H.I.E.L.D. project called "Phase Two." This project aimed to develop technologies capable of offering humanity some defense in the face of threats on the level of the Destroyer or the Abomination. S.H.I.E.L.D. researchers, including Erik Selvig, then reverse engineered the wrecked sentinel and developed the Destroyer Gun from its remains.

Coulson's Revenge
When Loki escaped confinement aboard the S.H.I.E.L.D. Helicarrier, S.H.I.E.L.D. agent Phil Coulson responded by retrieving the Destroyer Gun from secure storage. He confronted Loki, pointing the gun at him, and warned that he had no idea of its capabilities. Loki disguised his true location with illusion however, and stabbed Coulson from behind. As he lay dying, Agent Coulson managed to raise the weapon to fire off one powerful shot. The force of the impact was enough to severely hurt the god of mischief, but proved insufficient to prevent him from escaping.

Abilities
The Destroyer Gun was reverse-engineered from the ruined remains of the Asgardian sentinel known only as the Destroyer after it was destroyed by Thor. It appears to retain some part of the Destroyer's fiery core and can discharge powerful bolts of energy, producing heat, light and concussive force in the process. When the weapon charges up it gains a vivid orange glow emanating from between the banding plates around the barrel. A telescopic sight has been fitted to the top and other Earthly additions give this weapon a curious appearance, marrying modern technology with something altogether more alien.

Trivia

 * In Marvel: Avengers Alliance, this weapon Gun is named "Coulson's Revenge", a nod to The Avengers.