A different sort of vampire

Mark was bored. He couldn't pinpoint when he became aware of it. The knowledge just slowly grew until he wasn't only sure of it, but positive that he somehow had always known.
He seemed to know when he lived in the old shelter. It didn't have a roof and he felt lucky to have the four walls and floor. He and Edgar lived there, with the thin walls seperating them from the bright nothingness beyond. Sometimes they would jump up into that nothingness, feel their flesh burna s moisture began to leave them, and then fall back to safety.
It was dangerous. They couldn't pinpoint when they figured it out. One day Edgar stopped mark from jumping, and neither had done it again. Their desire to survive was stronger than their curiosity or bravado.
Edgar had as little to do as Mark. Edgar wasn't aware of this because he was insane. His days were filled with trying to spot creatures out in the nothingness. He once told mark that there was a giant fanged beast, a hundred times their size, hidden in the nothingness just outside the shelter. Mark began ignoring him, and without noticing it, realized how bored he was.
The new shelter was nicer. It was larger than the old one and had more stuff in it. Mark couldn't remember leaving the old shelter, just fragments or noise, light, the burning sensation of moisture vaporizing into the nothingness, and then a bug-eyed monster. The monster was named Neil, and was very self-conscious of his bulging eyes. Those were common for his kind, of which he was the last in the shelter.
Neil showed Mark around. There wasn't much to see so Neil led him through the castle and around the plastic coral after each stop. The new shelter even had it's own roof, too high to keep out the nothingness, yet low enough to add it's own sting to any leap.
There were others in the shelter, most were long and spindly, some species Mark had never seen before. Mark didn't speak to them, and avoided Neil when he could, but Edgar spent a lot of time talking with them. Whoever they were, they had connections, they seemed to be regularly giving Edgar packages.
Edgar hid the packages under the giant diver statue. Mark didn't know why, as he and Neil were the only ones in the shelter who didn't know what Edgar was getting. Neither had any interest either, which made hiding them even stranger. Mark assumed that Edgar was just acting out his insanity, but one day he was drawn in as well.
Mark was hanging out at the castle when Edgar came up and asked for help. "Help with what," Mark asked.
"Digging. I'm going to dig down find a way out. I'd just like you to help me move the rocks."
Mark agreed, and spent several days moving around the rocks that lined the shelter floor. He didn't assume it would work, but it put a dent in the boredom. The others came to watch, except Neil who was worried they'd all die if the floor was breached. Edgar didn't care. His plan seemed to involve a long piece of rope, a plastic tarp, and several of the smaller rocks.
They had dug all day, narrowly escaping several cave-ins, when Mark decided to take a break. The others watched Edgar, except Neil who hid in the castle practicing holding his breath. Mark went to the statue, curious now about what Edgar's plan entailed. He began digging out Edgars supplies. It was mostly ropes and tarps, dozens of each. The only other thing buried there was a clear plastic cylinder with something grey inside it labelled 'duraskin'.
Mark had a pretty good idea that the duraskin was to protect against the nothingness. The shelter walls held up against it, so they could be safe. Edgar had obviously found something that he thought could work, and there was no ignoring that Edgar had put a lot of thought into this plan. Feeling excited for the first time in what seemed forever, Mark opened the cylinder.
It was a suit, a grey suit with a strange number and assortment of limbs, as though it were not intended for their species. It wouldn't fit anyone in the shelter properly, but it only needed to fit well enough. Edgar was going to escape. There was only one suit, which meant that he was going to be left behind. Mark didn't want to be left behind, but everyone would know it was Edgar's plan, and would keep him from escaping.
Mark wasn't sure what to do, so he stared at the suit. The suit seemed to be getting larger, and Mark began to hope that it would be big enough to hold two. He stared at it, trying to make mental note of reference points to measure it's size. It wasn't until the eyepieces blinked that he realized it was staring back.

Goe, letting you know this ties into this, but the title is from a different half-written story just to keep you on your fins.