The 1987 musical Into the Woods weaves together several stories from the Brothers Grimm into one production. One of those stories is Jack and the Beanstalk, in which Jack trades his cow named Milky White for magic beans. The cow figures heavily in the rest of the story, so every stage production has a Milky White. The musical is quite popular, and is performed by high schools and community theater groups across the US. And they all have to put a cow on stage.
Not every production has the budget or the talent to put a professionally-designed cow on stage, so imagination is the main ingredient. The website Low Budget Milky Whites is dedicated to chronicling the most, um, imaginative ways that Milky White is played in Into the Woods.
Jacob Lowrey culled some of the best Milky Whites from Low Budget Milky Whites and other sources for an extensive Twitter thread.
Some are people dressed as a cow. Some are two people dressed as a cow. Some are cardboard cutouts, some are puppets, and some are toys. Some are life-size props on wheels. The replies have plenty of contributions from yet more productions.