Pirates? 

In Equestrian Space, a group of ships of alien origin waited for a passing Equiis cargo ship while cloaked. It passed in front of them and they drifted forwards, out of sight thanks for their cloaking mechanisms

Aboard the Equestrian ship

The systems didn't detect anything odd for the moment and the Equestrian walked down the corridor and noticed something outside the airlock, out of the corner of her eye. She backtracked up the corridor and turned to look out of it, and sure enough there was an alien with two odd looking swords standing in front of it, on the hull of the space ship. [img=http://img2.wikia.nocookie.net/__cb20140213002610/unhalo/images/e/ef/Gallery_9009_9_6944.jpg]
It tilted it's head and then slashed out and the blades began to cut through the door. She took a step backwards and turned to contact her fellow crew members, only to hit something in front of her as she tried to run and stumbled backwards to the floor. Slowly, another odd looking alien appeared and it took a moment for her to realise it was de cloaking, she scrambled backwards but it moved upon her and aimed a strange alien device towards her, before firing a single shot into her face. She screamed as the plasma burnt through her face.
In the next Corridor, another heard her screams and turned the corner to find himself face to face with an alien as it moved it's gun from his killed comrade to him. He turned and bolted off towards the bridge, the alien in hot pursuit. He arrived at the doors to bridge and they opened up to allow him inside... What awaited him was a horrible sight, as the bridge crew lay dead with some of the alien menaces over them. He began to cast a spell but was interupted by a sharp pain in his back, and he fell to the floor, immobilised as the blade pierced his spine. The aliens began to speak with one another in some unknown language, and in the view screens, as he last view, he could see a set of alien vessels appear and approach the vessel to load on the pirated goods.

The Alien Pirates jettisoned the cargo into space and abandoned the Equestrian ship, their ships picking up the cargo that had been dumped into space and gathering as much as they could before escaping, leaving a ghost ship with a dead crew floating in space. Less than ten seconds after they had left the system, the ships self destruct kicked in and obliterated the ship entirely.