Eaten Alive: A Tasteful Revenge 1999 on netflix

Stacey is an executive in a cosmetic and fashion company. Expecting a big promotion and crushed when her roommate, Lisa gets it instead, Stacey plans her revenge. Unknown to her boss and her fellow co-worker, Robin, Stacey has developed a shrinking ray with the help of Dr. Baines. She confronts Lisa first, shrinks her down to bite size and devours her. To eliminating any witnesses, Stacey eats Dr. Baines and then turns her attention to Robin and her boss, Trish. Each of them is reduced in size and then EATEN ALIVE!