Fathead wall graphics are constructed from 
tough, tear and fade-resistant vinyl
and feature high-resolution 3D graphics. 
Fatheads use a low-tack adhesive and
can be moved and reused without damaging surfaces.
Also includes smaller decals as shown.

Does it make any difference what kind of wall I put my FATHEAD on?

Yes. Fatheads need clean, smooth, dry walls. Pebbly or rough textured walls are not friendly to Fatheads so don't go there. It's OK to put your Fathead over wallpaper but it has to be clean, dry, and smooth. Some coatings applied to wallpaper to improve the ability to clean it can decrease stickiness so check frequently to see if your Fathead shows signs of peeling off. As a rule of thumb, if you run a tissue across the wall and it doesn't snag or pick up any dirt or residue, you're good to go. And remember, your Fathead was made for use indoors, so don't be putting it on the side of your RV.

Will my Fathead damage my wall?

No. Fatheads are perfectly safe for walls. The special low-tack adhesive does not leave any residue and will not pull off paint so long as the paint is in good condition and isn't already peeling. It's even safe to put up over wallpaper provided that the wallpaper itself adheres properly to the wall.