There's been a person defacing street art in New York City as of late. Nicknamed "the splasher", it seems he/she likes to splatter paint on existing street art in Brooklyn and Manhattan.
From the NYTimes article:
"Many of the paint splatters were accompanied by messages printed on plain white sheets of paper and pasted near the splatters. Those communiqués appeared to condemn the commodification of art, but it is difficult to be sure what the messages really mean. One reads, in part, “Destroy the museums, in the streets and everywhere.” The author has kept his or her identity a secret."
Link in the
Gothamist.
Also, an article in the
NYTimes
Edited to add images:
From the Gothamist page:
The splashing:
And the accompanying manifestos: