From the diary of Twilight Sparkle, lead scientist of Equestria's space division:

"When we first went into space, we knew we were heading into dangerous territory. We knew there was a chance we would encounter other beings, some of whom would be hostile. But we had no idea just how… bizarre some of the life forms we encountered would be.

"The ESS Ambassador was one of our earliest ships to explore deep space. During one such mission, it vanished without a trace. Ten years later, we managed to find it, and the flight recorder: The logs showed that the crew, having investigated signs of life on an uncharted world, encountered several lifeforms that managed to get onto the ship. Though our friends were equipped with the best defensive technology we had, it did nothing to slow down the creatures, who proceeded to hunt down and eat the entire crew, at which point the creatures then leapt out of the ship into the void of space, leaving the Ambassador to sail on as a ghost ship.

"Though the loss of the crew is a devastating setback, I tried to make their loss meaningful by analyzing every scrap of data about these creatures, which I termed, 'Gulpers.' My analysis was uploaded to the central computer; I didn't know it at the time, but it was only a glimpse at the creatures who have proven themselves as the apex species of our galaxy."