Final boss



The final boss, often called the Icon of Sin because of the Doom II level it forms part of, is the final boss of Doom II, in MAP30: Icon of Sin. See this walkthrough for a gameplay description of the boss in its original level.

In TNT: Evilution it is simply called the demon-spitter. In The Plutonia Experiment it serves as the Gatekeeper, and known in the Final Doom manual introductory story as Baphomet.

The final boss is not a monster in the technical sense, since it does not count towards the monster kills percentage at the end of a level, and is not affected by the command line parameters that affect standard monsters. Additionally, monsters are a single Doom thing, but the final boss is made up of a number of these:
 * Romero's head is the thing that must be destroyed. It starts with 250 hit points, but it is hard to hit due to its location deep in a hole.
 * A monster spawner in front of the head launches spawn cubes. This is reminiscent of how Satan gives birth to his daughter Sin in John Milton's Paradise Lost in that she is born out of his head (a parthenogenesis originally based on Zeus and his own daughter, Athena).
 * Several spawn spots are located around the map. These are where the skull adorned cubes land and spawn a monster.
 * Wall textures ZZZFACE1 through ZZZFACE9 are arranged to construct a demon face with a hole into its brain. This is what the player sees as the boss, but it has little to do with its functioning.

Details
The final boss is also displayed in the earlier MARBFACE texture.

It spawns a potentially endless series of monsters of demonic ilk (minus cyberdemons, spiderdemons, and zombies), all of which count towards the player's end-of-level kill percentage; as a consequence of this, the player can finish the level with a greater than 100% kill percentage.

The sound effects associated with the Icon are:
 * DSBOSSIT (wake-up noise)
 * DSBOSPIT (cube is fired)
 * DSBOSCUB (cube in flight)
 * DSTELEPT (cube turning into monster)
 * DSBOSPN (Romero's head takes damage)
 * DSBOSDTH</tt> (Romero's head dies)
 * DSBAREXP</tt> (explosions just before level ends)

Background
A quote from Robert Prince:

"It was a late night and the walls were shaking at id Software. Why? There could be only one reason -- Romero is in the building! Otherwise, it was a quiet, unassuming office -- better yet, a library. Then things quietened down, and I supposed that Romero had left. In fact, everyone but Romero had left, as I discovered when he came into the room I was using for "sound development." He sat down next to me and said that we needed a sound for the final boss to make when a player enters that level. I said that I had some possibilities roughed out and since he was there we could plug them into the code to see how they'd work. We went into John's office to look at the level (he had the only 21" screen). While he was whizzing around the level, all of a sudden he said, "Wait, what's that?" He had clipping off, which means that he could walk through otherwise "solid" objects. He had walked into the wall where the final boss head was attached. Lo and behold, there inside the brain of the boss was Romero's head on a stick! We both laughed a while and Romero decided that the artists (Adrian Carmack and Kevin Cloud) had put it there as a joke. As it turned out, John Carmack had programmed the code so that Romero's head was the object that a player had to hit in order to kill the boss. And this head was down a shaft inside of the wall so it was normally out of sight. It was at that point that Romero and I decided to record his voice and use it as the final boss sound. We went back into the sound room and John started saying different things in a very pumped up voice. He finally said, "To win the game, you must kill me, John Romero." I took that phrase and put some phasing on it and then reversed it. Shades of the rumors of "Satan" on different pop recordings! We decided not to tell anyone else what it said. We had the fun of seeing the artists' expressions when they first entered the level with this sound going. We made them sweat a long time before we played the phrase in its original form. Can you tell that we always had a great time doing this stuff?"

Trivia
Reversed, the DSBOSSIT</tt> is a distorted recording of John Romero saying to win the game you must kill me, John Romero.

The launch sound of the spawn cube (DSBOSPIT</tt>) comes from Sound Ideas' General series sound library: Disc 6015, track 28-1: "Fire,Ball - Impact and large fire burst, rumble." It is a very widely used sound effect that has also been used in several movies (such as Dragonheart) television series (for example, ReBoot and Xena: Warrior Princess) and documentaries (like The Hawking Paradox from BBC Horizon).

There's an interesting bug in the demon-spitter behaviour (at least in the original DOOM2.EXE), which doesn't affect any official IWAD but could affect a (badly-designed?) PWAD; if the monster spawn spot being aimed at is due east or due west of the demon spitter, the cube will miss the spot and carry on forever, even sailing through the walls of the level and eventually wrapping around to the other side of the map. This can result in an endless stream of spawn cubes crossing the level (or two such streams in opposite directions).