Chinese mystery snail is a large invasive snail that now occurs across much of North America. Recent work in Wisconsin found that Chinese mystery snail occurred in 50% of lakes surveyed in northern Wisconsin (Solomon et al. in press). Their occurrence was correlated with lake productivity and measures of human activity (number of boat landings, housing density). Overall, there was no effect of Chinese mystery snail on native snails, though many native snail species were found to have mysteriously disappeared since the 1930s. Although Chinese mystery snail is widespread and abundant in northern Wisconsin lakes, it does not appear to have strong impacts on native snails. Other potential effects have not yet been examined.