  We propose a new model for the formation of fast, low-ionization emission
regions (FLIERs) in planetary nebulae that is able to account for many of their
attendant characteristics and circumvent the problems on the
collimation/formation mechanisms found in previous studies. In this model,
FLIERs are formed in the stagnation zone of partially collimated stellar winds
with reduced momentum flow along the axis. A concave bow-shock structure is
formed due to the lack of momentum flow along the axis of a midly bipolar
stellar wind. The stagnation knots are formed when the shocked environment
medium accumulates at the apex of the outer shell and is compressed to a dense
knot in the {\em concave} section of the bow-shock. We present two-dimensional
hydrodynamic simulations of the formation of a stagnation knot and compare the
resultant dynamical properties with those of FLIERs in planetary nebulae.
