  We study the LHC discovery potential in the search for heavy neutral leptons
(HNL) with a new signature: a displaced shower in the CMS muon detector, giving
rise to a large cluster of hits forming a displaced shower. A new Delphes
module is used to model the CMS detector response for such displaced decays. We
reinterpret a dedicated CMS search for neutral long-lived particles decaying in
the CMS muon endcap detectors for the minimal HNL scenario. We demonstrate that
this new strategy is particularly sensitive to active-sterile mixings with
$\tau$ leptons, due to hadronic $\tau$ decays. HNL masses between $\sim 1 - 6$
GeV can be accessed for mixings as low as $|V_{\tau N}|^{2}\sim 10^{-7}$,
probing unique regions of parameter space in the $\tau$ sector.
