The katyusha is a type of helm in NetHack brass.

Though seemingly useless, the katyusha--a maid's frilled headband--gains some interesting properties when worn in conjunction with the maid dress by a female character. It grants 2 bonus AC, acts as a luckstone of the appropriate beatitude, and increases the player's Charisma by the amount of its enchantment.

It is inadvisable, however, to take advantage of this Charisma increase for encounters with incubi--despite its fetish appeal, you must still remove the maid dress beforehand!

A male character who wears the katyusha will only gain aggravate monster.