Ring of shooting stars (more or less a straightforward port of the ring of the same name from D&D): a chargeable ring which can be applied or invoked and then prompts for a direction. Once entered, a “shooting star” object (in the venom class?) flies in that direction, with no range limit, and explodes when it stops or hits the floor, possibly creating multiple explosions like the skilled fireball or cone of cold spell, and the ring loses a charge.

The damage type could be any of the following:

• Use AD_STAR from dNetHack (a damage type that deals physical damage and is also treated like silver for monsters which hate it), though this may be too much work to implement.
• Each use of the ring randomizes among physical, magic missile, fire, cold, and shock explosions. (If multiple explosions happen, they could all be of one type, or different.)
• Each individual ring deterministically randomizes from those damage types, and all explosions it produces will be of that type.

How the ring should work with negative charges is not well-defined. It should probably never generate with negative charges anyway, but options here include special-casing the ring so it can’t have negative charges, doing nothing while applied with negative charges, or consuming a negative charge, but with some bad effect like a large chance of exploding on the hero’s space.

This ring is a bit of an oddity in that it has no effect when worn. It probably should have to be worn in order to use it, which makes it more tactically interesting.