  The stellar cataclysms producing astronomical transients have long been
modeled as either a point-like explosion or jet-like engine ignited at the
center of a spherically symmetric star. However, many stars are observed, or
are expected on theoretical grounds, not to be precisely spherically symmetric,
but rather to have a slightly flattened geometry similar to that of an oblate
spheroid. Here we present axisymmetric two-dimensional hydrodynamical
simulations of the dynamics of point-like explosions initiated at the center of
an aspherical massive star with a range of oblateness. We refer to these
exploding aspherical stars as "ellipsars" in reference to the elliptical shape
of the iso-density contours of their progenitors in the two-dimensional
axisymmetric case. We find that ellipsars are capable of accelerating expanding
rings of relativistic ejecta which may lead to the production of astronomical
transients including low-luminosity GRBs, relativistic supernovae, and Fast
Blue Optical Transients (FBOTs.)
