The plucky teens from Hawkins, Indiana are back in Netflix's hotly anticipated Stranger Things season 3. You know that annoying houseguest who overstays their welcome and just won't leave? It looks like the interdimensional monster known as the Mind Flayer, from Stranger Things, may be one of those guests. That's the big takeaway from the latest trailer for season 3 of the popular Netflix series. (Some spoilers for the first two seasons below.) Stranger Things was an instant hit when it debuted on Netflix in the summer of 2016.