Reflection allows programmers to inspect and modify the structural and runtime properties of a software system. Traditionally, the architecture of a reflective system has been a monolithic part of the runtime system, featuring a fixed semantics. Mirror-based reflective architectures decouple the base-level entities from their meta-level counterparts. In this work, we explore ChromaKey, a design to go yet one step further. ChromaKey enables the user extend the reflective system in two dimensions: the semantics of reflective objects and reflection on syntax extensions of the host language. The first axis decouples the reflective system from a specific mirror interface. The second axis allows existing hierarchies of reflective objects to be extended. The key component is a generic reflecting component that "parses'' class definitions according to a given semantics, specified by generic factories (Object Algebras).