A grey-and-white checkerboard pattern that emulates a transparent background or alpha transparency within the image. The grey-and-white pattern comes from the way that transparency is shown in Adobe Photoshop and other programs.
In May 2019, it became a Twitter meme for artists to create art using fake transparency. This came from an event in which The Pokemon Company revealed a real life Geodude mascot for the prefecture of Iwate in Japan. Since Geodude doesn't have legs, the costume used fake transparency to "hide" the legs of the performer inside the costume.