Acclaimed street artist Banksy has crossed the pond from his native UK, and is now leaving his marks all around New York City. Since October 1st, he's created upwards of 10 pieces as part of his monthlong "residency" (to borrow a term from the professional art world), titled "Better Out Than In." Banksy's playful work often offers social or political commentary, and he hasn't limited himself to sidewalks and walls in New York — he's already created two mobile pieces on trucks. Many of the New York pieces include mock audio guides that poke fun at the recorded messages offered to museum-goers, which are also available online.

Banksy's work by its very nature is ephemeral — property owners often paint over it, or opportunistic looters extract it from the streets and sell it for vast sums, sometimes even chiseling it out of exterior walls. The short shelf-life of Banksy's work has never been more visible than here in New York. A little less than halfway through his tour of the Big Apple, local graffiti artists and property owners have already altered his first few pieces dramatically with their own marks. See the biggest transformations below. — Photography by William Mansell and Sam Sheffer.