This .NET class wraps the AcDbProxyEntity ObjectARX class. 

This abstract class provides an interface to the description data for the entities stored within ProxyEntities in drawings. It also provides access to an explode method that results in a set of entities that are copies of the graphics metafile data stored in the proxy.

Autodesk.AutoCAD.DatabaseServices.DBObject
    Autodesk.AutoCAD.DatabaseServices.Entity
        Autodesk.AutoCAD.DatabaseServices.ProxyEntity

Public sealed Class ProxyEntity
Inherits Entity

public sealed class ProxyEntity : Entity;

ProxyObject