In the original Resident Evil
Video Game on Playstation, released by Capcom in 1996, the game was so complex and there were so many enemies that the programmers were forced to remove the bodies of the killed enemies as soon as the player opened or closed a door, went up stairs, or somehow entered another scene; causing the old scene to revert to it's original condition and the enemies to re-populate.
The term "Resident Evil
Maid" was something my friend and I, and obviously others, came to call this new style of gameplay. previously, the graphics were not as complex, the games took nowhere near that time to complete, and there were no 'transitions' between entering or exiting a room.
The Resident Evil
Maid is so fast, that leaving a room and immediately re-entering is will remove the dead enemies in under one second.
The game was so groundbreaking that at the time more development went into this particular game than the console designers had expected. This is often referred to as the first game of its kind, and as such minor sacrifices although necessary, were very, very silly.