The Simulation Argument
This is a rather good list of existential risks facing humanity, including the usual suspects, but also the unusual “we’re living in a simulation and it gets shut down” risk:
A case can be made that the hypothesis that we are living in a computer simulation should be given a significant probability. The basic idea behind this so-called “Simulation argument” is that vast amounts of computing power may become available in the future, and that it could be used, among other things, to run large numbers of fine-grained simulations of past human civilizations. Under some not-too-implausible assumptions, the result can be that almost all minds like ours are simulated minds, and that we should therefore assign a significant probability to being such computer-emulated minds rather than the (subjectively indistinguishable) minds of originally evolved creatures. And if we are, we suffer the risk that the simulation may be shut down at any time.
While that may seem ludicrously sci-fi, the argument to consider it a distinct possibility is strong (there’s a good summary here). The happy ending? Even if we are all simulated, it makes no difference – you might as well go on living your life as if you were real. OK then.