User:Ion frigate/difficulty
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x small abomination  

Difficulty  5 
Attacks 
claw 11d2, claw 11d2 
Base level  3 
Base experience  80 
Speed  30 
Base AC  15 
Base MR  100 
Alignment  0 (neutral) 
Frequency (by normal means)  Common 
Genocidable  No 
Weight  5 
Nutritional value  0 
Size  Tiny 
Resistances  fire, cold, sleep, poison, shock, death magic, drain life, disintegration, stoning 
Resistances conveyed 
none 
A small abomination:

From source code found here, I infer that, in SLASH'EM, difficulty is computed as follows: We have an integer, n
Contents
Generation in groups
 +1 for small groups
 +2 for large groups
 +4 for very large groups
Ranged attacks
 +1 for any gaze, spit, breath, weapon or magic attack (all can be ranged)
Armor class
 +1 for base AC < 4
 +1 for base AC < 0 (these two combine)
Speed
 +1 if speed >= 18
Attacks
For each attack:
 +1 if it is not passive
 +1 if it is a magic (AT_MAGC) attack
 +1 if it is a weapon (AT_WEAP) attack, and monster has the M2_STRONG flag
 +2 if it is poisonous (AD_DRST, AD_DRDX, AD_DRCO), drain life (AD_DRLI), stoning (AD_STON) or lycanthropy (AD_WERE)
 +1 if it is not one of the immediate above, and is also not pure physical damage (AD_PHYS)
 +1 if it can do 24 or more "damage" (specifically, if it is ndm, if nm > 23); does not have to be physical damage
Nastiness
 +5 if it has the M2_NASTY flag (note that this does not seem to be true for vanilla NetHack, from checking monsters both with and without it, this formula matches for those without, but is off by the correct amount for those with that flag to mean that it is not factored into its calculations)
Difficulty
Then, we have tmp; if mlevel <= 49, tmp = mlevel; otherwise tmp = .5 * (mlevel  6) Now, what is difficulty?
 If n = 0, difficulty is tmp  1
 If 0 < n < 6, difficulty is tmp + 1 + n/3
 If n >= 6, difficulty is tmp + n/2
Rounding down for integer division