Abstract. The Pegasus Toroidal Experiment is a mid-sized extremely-low aspect ratio (A) spherical torus (ST). It has the dual roles of exploring limits of ST behavior as A approaches 1 and studying the physics of ST plasmas in the tokamak-spheromak overlap regime. Major parameters are R = 0.25 - 0.45 m, A = 1.1 - 1.4, Ip 0.15MA, and Bt < 0.07T. High beta plasmas are produced at very low toroidal field by ohmic heating. Values of toroidal beta up to 25% have been obtained, and the operational space of beta vs Ip/aBt is similar to that observed for NBI-heated START discharges. Achievable plasma current apparently is subject to a ``soft'' limit of Ip/Itf 1. Access to higher-current plasmas appears to be restricted by the appearance of large internal MHD activity, including m/n=2/1 and 3/2 modes. Recent experiments have begun to access ideal stability limits, with disruptions observed as q95 approaches 5, in agreement with numerical predictions.