Foocubus

Foocubi refers to an incubus or a succubus, especially one of the opposite sex of the character. These demons are generally used by high-level and high-charisma players for their beneficial effects. After an encounter you may "feel good enough to do it again;" your constitution has just increased by 1 and been exercised. You may instead "always remember the foocubus;" this increases and exercises wisdom. "You feel restored to health" will heal all your hit points and exercise strength. "You feel raised to your full potential" will increase your maximum power by 1-5 and restore all of it, and exercise constitution. A "very educational experience" will raise your level by 1 and exercise wisdom.

On the other hand, you might feel "down in the dumps" and lose 1 constitution, that "your senses are dulled" and lose 1 from wisdom, you might "feel exhausted" and lose some hit points, "drained of energy" and lose all your power and reduce maximum, or "out of shape" and lose a level. Afterwards, the foocubus will be a mite cantankerous, so avoid him/her for 1-100 turns.

Detailed Strategy
Foocubi may be randomly encountered, generated from figurines, or summoned by repeatedly kicking a sink. Other demons can summon them, but they cannot summon other demons, including other foocubi. They cannot be summoned by a cursed scroll of genocide.

The foocubus may begin the encounter of its own volition if it is hostile, or the player may begin the encounter with the #chat command.

The foocubus will attempt to remove all armor. With probability CHA/20, he/she will ask; otherwise he/she will just remove the item. This process repeats for each item of armor you are wearing, except that the foocubus can only remove your suit if you have not kept your cloak on, and can only remove your shirt if you have not kept your cloak or suit on. If at the end of this stage, you are still wearing a cloak or a suit, the foocubus will give up and teleport away.

The probability of a beneficial effect from the encounter is (INT+CHA+1)/35. It is therefore a good idea to maximize charisma before consorting with foocubi. Intelligence also helps, but intelligence is the most difficult score to raise.

One of the possible effects of a magic trap is that "You feel charismatic!", and gain a point of charisma and possibly some unusual pets. Repeatedly stepping on a magic trap is the easiest way to raise charisma, but it has some hazards. One is that it will often blind the player and summon lots of monsters; another is a tower of flame, as from stepping on a fire trap. It helps to have telepathy, and to be a capable fighter, to deal with the monsters. Fire resistance is also a good idea.

A ring of adornment can raise (or lower) charisma; but foocubi take an interest in them. An incubus may put it on your finger; a succubus may ask you for it, or just take it. The probability of asking, rather than just doing, is in both cases CHA/20 (where CHA is your charisma before donning or doffing the ring). A female character has a small advantage here, as she can keep a positively-enchanted ring on and it will boost her chance of a positive effect. A male can only do this reliably if his charisma is thus boosted to at least 20, as the succubus will otherwise eventually steal the ring. On the other hand, males need not ever worry about negatively-enchanted rings of adornment, nor having a ring of levitation replaced by a ring of adornment and possibly dropping him into water or lava.

A helm of brilliance can raise (or lower) intelligence. As with all armor, the foocubus may try to take it off; with probability CHA/20, he/she will ask instead of just removing the helmet. Unlike rings of adornment, the foocubus will never keep the helmet; thus you can put it back on and still get the boost when you try again. Negative enchantments need not cause concern, as you can always give consent to take the helmet off.

After the encounter, the foocubus will try to take some of your gold, failing with probability CHA/20. If you got a positive effect, the foocubus will complain of having a headache and will do you no more favors for 1-100 turns. If you got a negative effect, the foocubus will be ready to go again immediately. However, in either case, there is a 1 in 25 chance that the foocubus will become cancelled, as if struck by the wand, and will do you no more favors; in that case he/she will complain of a severe headache. The only thing to do with a cancelled foocubus is to kill it.

Possible YASDs
There are several ways a foocubus can kill you outright; but they are generally easy to avoid.

Be cautious when using boots of levitation or water walking; the foocubus may remove them, dropping you into water or lava.

Females should be similarly cautious when using a ring of levitation, wearing a second ring, and carrying a ring of adornment; the incubus may replace the ring of levitation with the ring of adornment.

Avoid wielding cockatrice corpses around foocubi unless you have charisma of 20 or more; he/she may remove your gloves.

Characters at experience level 1 should stay well away from foocubi, as one of the possible negative outcomes is a level drain. In practice, this means that low-level characters should not kick sinks.

Removing cursed items
Foocubi can remove any armor, including cursed armor; succubi can also remove cursed rings of adornment from male characters. This provides an alternative to nymphs for ridding oneself of such items.