Graphical user interfaces are typically designed as one-size-fits-all solutions, offering limited accommodation for the diverse needs, preferences, and abilities of end-users. MorphGUI introduces a real-time GUI customization approach that leverages Large Language Models to let users reshape live interfaces through natural language requests. Users can describe how they would like an interface to look or behave, and the system applies the requested modifications on the fly, without requiring access to source code or specialized development skills. We describe the design and implementation of MorphGUI, discuss how LLMs are guided to produce safe and consistent interface edits, and report on a user study assessing its usability, expressiveness, and limitations. Results suggest that real-time, language-driven customization can significantly lower the barrier to personalizing everyday software, while also highlighting open challenges around reliability, trust, and the co-design of adaptive interfaces.