This demo paper presents the technical details and usage scenarios of $mu$SE: a mutation-based tool for evaluating security-focused static analysis tools for Android. Mutation testing is generally used by software practitioners to assess the robustness of a given test-suite. However, we leverage this technique to systematically evaluate static analysis tools and uncover and document soundness issues. $mu$SEs analysis has found 25 previously undocumented flaws in static data leak detection tools for Android. $mu$SE offers four mutation schemes, namely Reachability, Complex-reachability, TaintSink, and ScopeSink, which determine the locations of seeded mutants. Furthermore, the user can extend $mu$SE by customizing the API calls targeted by the mutation analysis. $mu$SE is also practical, as it makes use of filtering techniques based on compilation and execution criteria that reduces the number of ineffective mutations.