Ready to dive into the deep end of the humor pool? These dark humor Tumblr memes are here to tickle your funny bone—in the most twisted way possible. We bring you, Tumblr After Dark. From jokes ...

The joke appeared in meme form in Nov. 2013, with a Tumblr post. The image macro depicted a bathroom sink in front of a door with a speech bubble that reads “knock knock.” The caption reads ...