Player/missile graphics
Atari's own take on hardware sprites: narrow, screen-tall strips that move freely sideways and are collision-checked by the chip itself.
The name comes straight from arcade shooters. The Atari 2600's TIA had two "players" and two "missiles", and the 8-bit home computers of 1979 expanded that to four players, eight pixels wide, and four two-pixel missiles. The four missiles could be ganged together into a fifth player. Each object is a strip running the full height of the screen; the program draws the shape into the right rows of a memory area and moves the strip horizontally with a single register write.
The chip records every overlap between players, missiles and playfield colours in collision registers, so the game can simply ask instead of computing it. Combined with display list interrupts, the same player could be reused further down the screen, the trick later known as sprite multiplexing.