Extinctionism

Extinctionisim is the act of causing every creature in the game of Nethack to become extinct. A creature is extinct when 120 of it's kind have been born.

How to extinct creatures
A creature is extinct when 120 of it's kind are born. The creatures do not have to be killed in order to be extinct. Once extinct, a creature will never be randomly generated again.

Therefore, you can extinct a creature simply by summoning, or reverse-genociding 120 of it's kind. Killing it is optional, but highly reccomended.

To extinct a creature, you must create it in a way that respects extinction.

Actions that respect extinction

 * Reverse-genociding a monster.
 * Casting create monster via spell, scroll or wand.
 * Waiting around on a level for it to be randomly generated.
 * Entering a level containing a special room such as a zoo, or beehive.

Play styles for an extinctionist
The easiest way to play an extinctionist, is to play as a wizard. The wizard has the ability to cast create monster with no hunger penalty, and with the Eye of the Aethiopica he can cast virtually indefinately. There is no reason another class couldn't do extinctionism, it is simply more challenging as another class.

Once you have the quest artifact, make sure to gather up all the various resistances, including magic resistance, and reflection. It would be very bad to lose your character to a random gnome with a wand of death. Make sure you have a decent set of armor, and a good weapon as well.

A common method to rack up kills is to build a boulder fort around an altar. Then stand behind the altar and cast create monster over and over, while killing the resulting monsters and sacrificing them to your god.

You can either just summon monsters and kill them at random, or try to control your summoning.

Controlling your summoning can be done by carefully regulating your own experience level, and picking which dungeon level to summon the monsters on. By keeping your experience level low, you force the game to only summon monsters of a particular difficulty or lower. In this way you can wipe out all the lower level monsters, casting and killing until create monster fails. You can then move down a dungeon level, or gain an experience level to increase the monster difficulty.