Hardware sprite
A video chip's ability to hold a few small movable images with their own coordinates and composite them over the background as the beam draws — moving graphics without the CPU touching a pixel.
Before frame buffers were cheap, home computers couldn't redraw the screen every frame. The answer lived in the video chip: it held a fixed number of small bitmaps — sprites — each with its own position, and merged them with the background line by line as the beam swept. The Commodore 64's VIC-II gave you eight, with built-in collision detection; the NES OAM held 64 but only eight per line.
The limits shaped the games. Exceed the per-line count and sprites flickered or vanished — hence sprite multiplexing, repositioning a sprite mid-screen via a raster interrupt. When blitters and later GPUs turned everything into drawn quads, the dedicated hardware disappeared.