Worst-case scenario: the UEd Goblin wipes the map and burns down your house.

From Unreal Wiki, The Unreal Engine Documentation Site

Package: 

Core

Direct subclass:

Actor

This class in other games:

RTNP, U1, U2, U2XMP, UDK, UE2Runtime, UT, UT2003, UT2004, UT3

The top-most class of the UnrealScript class hierarchy in all Unreal Engine games. All other classes, even interfaces in games that support them, directly or indirectly extend the Object class.

Note the distinction between the Object class itself and an object as an instance of a class in general. Another distinction often made is between "actors" as instances of Actor subclasses and "non-actor objects" as instances of classes that do not extend Actor. Actors are created either by a mapper placing them in the level or at runtime with the Actor.Spawn() function. Non-actor objects on the other hand can be created in various ways in the editor, such as creating or importing resources or creating new object values in an actor properties window. At runtime, new instances for non-actor classes can be created with the new operator.

[edit] Properties

The Object class defines only few basic properties, all of which are defined when the object is created and cannot be changed later at runtime. (const. In the editor renaming or moving resources is possible only via a special editor feature, not by directly editing the object properties. (editconst)

[edit] Property group 'Object'

[edit] Name

Type: name

The name of this object.

[edit] Internal variables

[edit] Class

Type: Class

The class of this object.

[edit] Outer

Type: Object

The outer object containing this object. For resources like Textures this is usually the package or group, for Actors this is usually the map package of the level currently being played.

[edit] Enums

[edit] Structs

Some commonly used types that seem to be built-in types, such as vector or rotator, are actually structs defined in the Object class so they are available everywhere.

[edit] Operators

The Object class defines most of the operators you can use in UnrealScript code. Only a few special operators, such as the assignment operator =, the conditional operator ? : or the (in)equality comparison operators == and != for structs in general are implicitly available because they cannot be expressed in a standard operator declaration. All others actually have a declaration in UnrealScript, usually in the Object class so they are globally available.

[edit] Functions

The object class also defines many functions so they are globally available.