Activating a gameobject upon anothers destruction?

Questions & Answers
1

I need to activate a gameobject when another gameobject is destroyed. How would I go about this? (I know how to destroy my game object, what I need is the activation part.)

2

You need to use SetActiveRecursivley (if the object is already in the scene) http://unity3d.com/support/documentation/ScriptReference/GameObject.SetActiveRecursively.html

If you want to create a new object from a prefab you need instantiate http://unity3d.com/support/documentation/ScriptReference/Object.Instantiate.html

You can call these in multiple ways, including the onDisable
http://unity3d.com/support/documentation/ScriptReference/MonoBehaviour.OnDisable.html