How to use a static var

This is done on purpose. Static members of a class are global variables, and thus should not in practice be editable outside of the class, or without calling the class directly.

In normal programming, you typically don't want to use static variables because this can lead to improper accessing of said variable, which in turn could cause problems down the road. Typically, you'll want to make a variable public or private, and access it by creating a new instance of the class itself, and changing the property by accessing that instance of the class, which is one of the reasons they call it Object Oriented Programming.

In any case, like I said static variables are meant to not be accessed by the inspector. You have to set it before or during runtime in order to set it's value, with something like GameObject.Find(), Resources.Load(), etc. Do so in Start() or Awake() to initialize it, and then you can call it just fine.

So I think you're trying to make other game objects invisible from a controller/manager type object, right?

Static variables would probably not be the way to do this, static variables are global variables that persist throughout changes in the game, it's good for things like score or player health as the player travels through several different scenes. More on global variables can be found here at the very helpful scripting reference Scripting Reference Global Variables.

What I believe you should do is instead get a reference to the object you're intending to make invisible and then access the renderer that way. You can do as follows:

 var bodyPart1 : GameObject;
 var bodyPart2 : GameObject;

Then save the script, attach it to your controller, drag the references over in your inspector then the following will work inside your health controller script:

 bodyPart1.renderer.enabled = false;
 bodyPart2.renderer.enabled = true;

The renderer component is part of the GameObject, you were trying to do it via the transform which wouldn't work.

If you wanted to access the health controller script from elsewhere you could make an accessor function in the health control script, then get a reference to that script and call the function.

 var HealthControl : HealthControlScriptName;
 

Then drag a reference with the inspector and inside the script that accesses the HealthControlScriptName the make a function call like

 HealthControl.HideBody1(true);
 HealthControl.HideBody2(false);

and inside of the HealthControlScriptName you can fill out the functions like:

 public function HideBody1(hideIt : Bool)
 {
    bodyPart1.renderer.enabled = !hideIt;
 }

 public function HideBody2(hideIt : Bool)
 {
    bodyPart2.renderer.enabled = !hideIt;
 }

This, when called, will hide or unhide the body part. Do you want to hide bodyPart1? Call HideBody1(true). Unhide it with HideBody1(false). The public keyword is what you intend to do with static, I believe. It allows access through other scripts when you have the reference to the script that holds the public functions.

Make sense? This is what you needed?