Final answer:
Mylan NV increased the price of the EpiPen by 550% in 2016, leading to public outcry and media scrutiny.
Step-by-step explanation:
The product that Mylan NV bumped up the price of by 550% is the EpiPen. In 2016, Mylan faced backlash and media criticism for the significant increase in the price of EpiPens. The price hike resulted in public outrage due to the essential nature of the product and the seemingly excessive profits made by the company.