As you enter the park, you find it empty, no people, no animals, not even any bugs or trees. There's literally nothing here, nothing except you the grass and the mossy cement path you're walking on. You find this odd, for a split second you consider turning back and going home... but you're no coward, you fear nothing! Err, but you're not afraid of the nothing in the park.
You proceed further, following the moss-covered path. You keep following the path for a good fifteen minutes before the path ends.
With nothing to do you look around. There's still nothing here, nothing more than there was anywhere else in this park at least. You look into the sky, it's getting dark, that's strange, you know you were in the park for a while, but... should it really be this late already? Well, if it IS this late than you guess it should be. You decide it'd be best to head home, you can always explore the park again tomorrow, right?
You spin on your heel to face the way you came from.
Snap.
What was that? You remain where you stand, you slowly look around, take in your surroundings. It's getting dark out, but it's still pretty clear, if something were around you'd be able to see it... but there's nothing. You keep telling yourself that, but it doesn't help. You take a step back. Your back hits something. Beads of sweat are rolling down the back of your neck, it's becoming hard to breathe. You slowly turn around to see what is obstructing your path.
It's just more nothing. There's nothing behind you, or in front of you. There's NOTHING anywhere in this park.
Somehow that isn't a relief.
No. There can't be nothing here, you FELT something. You reach out with one hand, it makes contact with a smooth surface. There is definitely something there. You can't see it, but it's there. You begin sliding your hands around, examining this object that you cannot see. It doesn't take long for you to find a small knob protruding from the invisible structure.
Curiosity gets the better of you and before you know it you grip the knob and turn it. Suddenly there's a doorway in front of you. You step inside, closing the doorway behind you.
You look around, this appears to be some sort of science lab. There are computer monitors as far as the eye can see. Solutions of all colors bubble soothingly in vials and beakers throughout the room. There is a ladder on the far wall that leads down, no doubt to even more wonders.
You walk over to one of the computer monitors to have a closer look. It's a screen saver. Nobody's around, what harm can come from taking a peek, right? You push the mouse ever so slightly and the monitor flickers to life. The screen is covered in complex equations and notes with so many big words you aren't even sure it's speaking English.
Maybe one of the other monitors makes more sense? You turn to check, but accidentally bump into a table. One of the many beakers of colorful liquids (this one a dark shade of yellow-green) is bumped loose and begins rolling toward the edge of the table.
"No, no, no." You say aloud as you reach for the beaker. The beaker grazes your fingers as it falls from the table, you missed catching it by no more than two inches. But alas the beaker falls to the floor and shatters. In the enclosed room the sound of breaking glass echoes for a couple seconds.
"Did you hear that?" You hear a distant voice say, you don't hear a reply but it's safe to assume that there are at least two people here besides yourself. You assume it came from the bottom of the ladder. Oh no. Somebody else is here... you begin to panic, a lump appears in your throat. Your eyes fixate on the door from which you entered. It's your only choice, you've got to make a run for it. You take a step toward the door, only to have your foot land directly in the center of the yellow-green liquid from the broken beaker, your foot slips backward and you tumble forward, landing directly in the puddle getting the yellow-green liquid all over yourself. Your shirt is ruined and your hands are riddled with tiny shards of the broken beaker.
You remain on the floor for a moment. Until, that is, you here footsteps in the distance, slowly getting closer. You pull yourself to your feet and run to the exit. You push open the door and peer out into the emptiness that is the park. You can hear that the footsteps have stopped, no rather they've changed to the noise of a person climbing a ladder. The other person is almost here.
Without a moment to lose you bolt out the door and start running for home.
Stopping only meters from the invisible building when you hear something... something right behind you. You can feel its warm, moist breath on the back of your neck. Unsure of whether or not you're about to pee your pants, you turn around to view your aggressor. You don't see anybody there... but you can still feel it breathing. There is, without a doubt, something there. It hasn't attacked you yet. Maybe it's friendly? No, nothing is ever friendly if it breaths down your neck like a stalker.
You weigh your options. You have a few options.
Do you want to retreat and try to get the hell out of this park as fast as possible? Maybe you'd rather run back to the Secret Lab? Or perhaps you're more of the "stand and fight" type? Would you like to try to stand up to this invisible gargantuan? Maybe you'd rather do something else...