  Magnetic skyrmions are topological magnetic spin structures exhibiting
particle-like behaviour. They are of strong interest from a fundamental
viewpoint and for application, where they have potential to act as information
carriers in future low-power computing technologies. Importantly, skyrmions
have high physical stability because of topological protection. However, they
have potential to deform according to their local energy environment. Here we
demonstrate that, in regions of high exchange energy density, skyrmions may
exhibit such extreme deformation that spontaneous merging with nearest
neighbours or spawning new skyrmions is favoured to attain a lower energy
state. Using transmission electron microscopy and a high-speed imaging
detector, we observe dynamics involving distinct configurational states, in
which transitions are accompanied by spontaneous creation or annihilation of
skyrmions. These observations raise important questions regarding the limits of
skyrmion stability and topological charge conservation, while also suggesting a
means of control of skyrmion creation and annihilation.
