With the proliferation of wireless devices with embedded processors, there is an increasing desire to deploy applications that run transparently over the varied architectures of these devices. Virtual machines are one solution for code mobility, providing a virtualized processor architecture that is implemented over the individual node architectures. Proposed virtual machines for embedded systems are generally slow and consume significant energy, making them unsuitable for devices with limited processing power and energy resources. Presented is a novel virtual machine architecture, Scylla, specially designed for mobile embedded systems, that is simple, fast and robust. In addition to a basic instruction set, Scylla supports inter-device communication, power management and error recovery. To make on-the-fly compilation extremely efficient, the instruction set closely matches popular processor architectures that can be found in embedded systems today. This paper describes Scylla, along with a preliminary evaluation of its performance, including the costs of the on-the-fly compilation and the overhead of having a virtual machine, based on simulations and measurements on a prototype system.