Popsugar Entertainment Ma Ma Horror Movie Cast Meet Everyone Who Gets Terrorized by Octavia Spencer in Ma 30 May 2019 by Quinn Keaney View On One Page Photo 11 of 11 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 11 Allison Janney as Doctor Brooks How the movie studio got Oscar-winner Allison Janney to cameo as Ma's foul-mouthed vet, I'll never know. Previous Next Start Slideshow MaHorrorMoviesOctavia Spencer