  Starting from the asymptotic kinematics of massless scalar fields near null
infinity in any spacetime dimension, we build two higher-spin extensions of the
Carrollian definition of the BMS group and its generalisations. The first
extension exhibits conformal properties reminiscent of the singleton in Anti-de
Sitter space. The second acts on the space of radiative solutions of the
d'Alembert equation, i.e. on Sachs's representation of BMS, which we relate to
the scalar massless Poincare representation and extend to any Carrollian
manifold. The corresponding enveloping algebra is a higher-spin extension of
BMS that can be interpreted as the asymptotic symmetry of a putative exotic
higher-spin gravity theory around Minkowski spacetime. Along the way, we
provide a pedagogical introduction to Carrollian geometry and its relation to
BMS.
