  Magnetic biskyrmions are observed in experiments but their existences are
still under debate. In this work, we present the existence of biskyrmions in a
magnetic film with tilted uniaxial anisotropy via micromagnetic simulations. We
find biskyrmions and bubbles share a unified three-dimensional structure, in
which the relative position of two intrinsic Bloch points dominates the
two-dimensional topological property in the film middle. The film edge can
drive Bloch points and transform bubbles into biskyrmions via the demagnetizing
field. This mechanism is found in the formation process of biskyrmions in
confined geometry under zero field. Our work clarifies the structure and
formation mechanism of biskyrmions, emphasizing the three-dimensional aspect of
skyrmion-related nanostructures.
