On March 19, 2019, the Stranger Things social media accounts posted a short clip of rats scurrying through a dilapidated industrial area with the caption "It's almost feeding time."[67] This turned out to be a prelude to the release of stills and the first official trailer the next day on March 20.[68][69] The trailer quickly became the most-watched video on Netflix's YouTube channel, amassing 22 million views in the first week following its release.[70] On May 21, the first clip from the season was released in tandem with cast posters.[71][72] The clip, which features Billy flirting with Karen Wheeler at the local pool, includes notable references to the early-1980s comedy films Caddyshack and Fast Times at Ridgemont High.[71] Netflix released the final trailer on June 20, 2019.[73]