In this directed case study, students determine the impact of various venoms or disorders on the electrophysiology of neurons. Students begin with a review of basic neuron terms, physiology, and polarization, with particular emphasis on leak and voltage-gated channels. They then apply their knowledge to four fictional patients, three of whom have been exposed to a toxin (tetrodotoxin, maurotoxin, and a toxin that alters voltage-gated sodium channel gate dynamics); the fourth patient is hypokalemic and has thyrotoxic periodic paralysis. Students are asked to graph action potentials for each of the patients and describe what is happening with ion flow. This case study was developed to help students grasp how channel structure relates to channel function and ion flow, and how channel dynamics are critical for neurophysiology. It was developed for a non-majors, pre-nursing anatomy and physiology course for first- and second-year college students. This case study was inspired in part by two others in the NCCSTS collection, “Bad Fish” and “Lee Family Problems,” and can be used as a follow-up to the latter.