A modified silica microsphere was demonstrated for random laser generation. A conventional microsphere was fabricated in an optical fiber tip through electric arc discharge, and modifications to its geometry were carried out to create asymmetry inside the silica structure. The resulting Bunimovich stadium-like microsphere promotes multiple reflections with the boundaries, following the stochastic properties of a dynamic billiards. The interference of the multiple scattered beams generates a random signal whose intensity was increased by sputter-coating the microsphere with a gold thin film. The random signal is amplified using an EDFA in a ring cavity configuration with feedback, and lasing is identified as temporal and spectral random variations of the signal between consecutive measurements.