A skybox is a picture that wraps around the playing feild. Its completely 2D. So no you cannot interact with it.

"Munchkin: One who, on being told that this is a game about politics and intrigue in 17th century Italy, asks to play a ninja."
— Andrew Rilstone

Imagine an ordinary Battlefield level as a box that you play inside.
The bottom is the level itself with terrain, players etc.
The sides and top of the box are painted with the skybox, ordinary a blue sky.
Now if you change the skybox from a blue sky to an image of space, you would appear to be in space.
On the skybox you can also paint whatever you want, like a deathstar, but you will not be able to reach it since it's not part of the level, but wrapped around it.