It's a photograph that has now become an iconic image of the Occupy Wall Street movement. During a protest at UC Davis, a police officer in riot gear - later identified as Lt. John Pike - was filmed walking in front of seated student protesters, blasting pepper spray into their faces. The students had interlocked arms to prevent officers from taking them away.
The incident has led to calls for University of California Davis Chancellor Linda Katehi to resign (she said she found the images "chilling") as well as public outcry in general over the use of pepper spray by authorities on otherwise non-violent targets.
It has also led to a new Internet meme, in which the image of Lt. Pike and his pepper spray dispenser are placed in unlikely and humorous scenarios that highlight it as a violent and over-the-top reaction to something non-threatening. (The meme is alternately referred to as the "Pepper Spray Meme" or the "Scumbag Pike" meme, a reference to the ongoing "Scumbag" series of memes and again meant to ridicule Pike as craven and abusing his authority.)
This list represents the very best - thus far - of the Lt. Pike Pepper Spray meme. (With special thanks to Kwikset on Tumblr, the Google Plus feeds of Billy Galbreath and Sage Serif and @Xeni on Twitter for pointing me to some of these great entries.)