  Vesicles are soft elastic bodies with distinctive mechanical properties such
as bending resistance, membrane fluidity, and their strong ability to deform,
mimicking some properties of biological cells. While previous three-dimensional
(3D) studies have identified stationary shapes such as slipper and axisymmetric
ones, we report a complete phase diagram of 3D vesicle dynamics in a bounded
Poiseuille flow with two more oscillatory dynamics, 3D snaking and swirling. 3D
snaking is characterized by planar oscillatory motion of the mass center and
shape deformations, which is unstable and leads to swirling or slipper.
Swirling emerges from supercritical pitchfork bifurcation. The mass center
moves along a helix, the preserved shape rolls on itself and spins around the
flow direction. Swirling can coexist with slipper.
