Anthropogenic non-native species introductions are noted with concern when an animal population becomes established, individuals become numerous, and dire ecological consequences result. Examples are numerous where intentional or unintentional human facilitation of species introductions result in native species loss and extinctions, changes in vegetation composition or structure, loss of ecosystem functioning, introduction of non-native pathogens and parasites, and other consequences, and control/ eradication focus is rightly placed on extant non-native populations. Receiving much less attention are those instances where a population is introduced, grows to attain potential noxious invader status, and winks out, with no remnant of the formerly abundant species. To our knowledge, such an example is heretofore unknown among snakes. Here we report on the historic establishment, proliferation, and extirpation of a population of diamond-backed watersnake (Nerodia rhombifer) in Northern California. Museum records, newspaper accounts, personal interviews and unpublished reports help us reconstruct the history and demise of the population, and we place this knowledge within the context of other documented boom/bust populations for similar vertebrate groups.