  Frustrated systems exhibit remarkable properties due to the high degeneracy
of their ground states. Stabilised by competing interactions, a rich diversity
of typically nanometre-sized phase structures appear in polymer and colloidal
systems, while the surface of ice pre-melts due to geometrically frustrated
interactions. Atomic spin systems where magnetic interactions are frustrated by
lattice geometry provide a fruitful source of emergent phenomena, such as
fractionalised excitations analogous to magnetic monopoles. The degeneracy
inherent in frustrated systems may prevail all the way down to absolute zero
temperature, or it may be lifted by small perturbations or entropic effects. In
the geometrically frustrated Ising--like magnet Ca3Co2O6, we follow the
temporal and spatial evolution of nanoscale magnetic fluctuations firmly
embedded inside the spin--density--wave magnetic structure. These fluctuations
are a signature of a competing ferrimagnetic phase with an incommensurability
that is different from, but determined by the host. As the temperature is
lowered, the fluctuations slow down into a super-paramagnetic regime of stable
spatiotemporal nano-structures.
