Electrostatic discharge (ESD) has been shown to cause severe reliability hazards at the physical level, resulting in permanent and transient errors. We present the first analysis of the effects of ESD-induced errors on instruction-level computation. Our data were measured on a microcontroller test chip fabricated for this study, with discharges from a controlled ESD gun. cosmic-ray-induced soft errors have been widely researched, and modeled as single event upsets (SEUs). Our observations across multiple trials on 3 test chips show that in contrast to radiation-induced errors, ESD can cause much more widespread errors than SEUs. In our trials, we observed system hangs and clock glitches which are serious errors. We also observed errors in the following categories: multiple-bit corruptions across multiple registers, multiple-bit corruptions in the same register, and single-bit corruptions across multiple registers. At the instruction level, these errors manifest as system hangs or serious malfunctioning of I/O operations, interrupt operations, and data/program memory. We demonstrate that ESD-induced errors form a significant reliability threat to higher-level functionality, warranting modeling and mitigation techniques.