Monsters may be generated with a miscellaneous item if that monster's level equals or exceeds the roll of a d100.
The following monster types are ineligible for miscellaneous items:
- Monsters with explosion attacks
- Mindless monsters
- Ghosts and shades
- Keystone Kops of any rank
If the monster's difficulty is 5 or less, it has a 1⁄30 chance of receiving a polymorph item, which will be a wand of polymorph 1⁄6th of the time, or else a potion of polymorph. Otherwise, if the monster is living (e.g excluding undead, golems, and vortices among others), it has a 1⁄40 chance of receiving an amulet of life saving.
Otherwise, the monster gets an item from one of these sets, with each set equally likely:
- a wand of speed monster (1⁄6th of the time) or a potion of speed
- a wand of make invisible (1⁄6th of the time) or a potion of invisibility - or neither if the monster is peaceful and the player cannot currently see invisible
- a potion of gain level
Guards will not use speed-boosting items, and according to the code are not meant to receive them - however,
mtmp->isgd is only set after
makemon() is called, thus making it possible for them to generate with one. In practice, this only means that you will occasionally find a potion of speed or wand of speed monster in a deceased guard's inventory. 
- Guards, shopkeepers, and priests will not quaff a cursed potion of gain level.
- Peaceful, non-invisible monsters will not use a wand of make invisible or potion of invisibility, unless you can see invisible.
- Guards will not use a potion of speed or wand of speed monster.