A zombie (Haitian French: zombi, Haitian Creole: zonbi) is a fictional undead being created through the reanimation of a human corpse. Zombies are most commonly found in horror and fantasy genre works. The term comes from Haitian folklore, where a zombie is a dead body reanimated through various methods, most commonly magic. Modern depictions of the reanimation of the dead do not necessarily involve magic but often invoke science fictional methods such as carriers, radiation, mental diseases, vectors, pathogens, scientific accidents, etc. The English word "zombie" is first recorded in 1819, in a history of Brazil by the poet Robert Southey, in the form of "zombi". The Oxford English Dictionary gives the origin of the word as West African, and compares it to the Kongo words nzambi (god) and zumbi (fetish).
Chroma key compositing, or chroma keying, is a special effects / post-production technique for compositing (layering) two images or video streams together based on color hues (chroma range). The technique has been used heavily in many fields to remove a background from the subject of a photo or video – particularly the newscasting, motion picture and videogame industries. A color range in the foreground footage is made transparent, allowing separately filmed background footage or a static image to be inserted into the scene. The chroma keying technique is commonly used in video production and post-production. This technique is also referred to as color keying, colour-separation overlay (CSO; primarily by the BBC), or by various terms for specific color-related variants such as green screen, and blue screen – chroma keying can be done with backgrounds of any color that are uniform and distinct, but green and blue backgrounds are more commonly used because they differ most distinctly in hue from most human skin colors. No part of the subject being filmed or photographed may duplicate the color used as the backing.