  We propose a quartic chiral term $m_x m_y m_z \nabla \cdot \mathbf{m}$ for
the energy density of a cubic ferromagnet with broken parity symmetry (point
group $T_d$). We demonstrate that this interaction causes a phase transition
from a collinear ferromagnetic state to a non-collinear magnetic cone ground
state provided its strength exceeds the geometric mean of magnetic exchange and
cubic anisotropy. The corresponding non-collinear ground state may also be
additionally stabilized by an external magnetic field pointing along certain
crystallographic directions. The four-spin chiral exchange does also manifest
itself in peculiar magnon spectra and favors spin waves with the wave vector
that is perpendicular to the average magnetization direction.
