  Long-lived, colour-triplet scalars are a generic prediction of unnatural, or
split, composite Higgs models where the spontaneous global-symmetry breaking
scale $f \gtrsim 10$ TeV and an unbroken $SU(5)$ symmetry is preserved. Since
the triplet scalars are pseudo Nambu-Goldstone bosons they are split from the
much heavier composite-sector resonances and are the lightest exotic, coloured
states. This makes them ideal to search for at colliders. Due to discrete
symmetries the triplet scalar decays via a dimension-six term and given the
large suppression scale $f$ is often metastable. We show that existing searches
for collider-stable R-hadrons from Run-I at the LHC forbid a triplet scalar
mass below 845 GeV, whereas with $300\,\mathrm{fb}^{-1}$ at 13 TeV triplet
scalar masses up to 1.4 TeV can be discovered. For shorter lifetimes
displaced-vertex searches provide a discovery reach of up to 1.8 TeV. In
addition we present exclusion and discovery reaches of future hadron colliders
as well as indirect limits that arise from modifications of the Higgs
couplings.
