When a player is killed by a giant spider and leaves bones, there will be a web trap placed on their square, and occasionally one or two giant spider eggs.

Giant spiders currently just use the generic encyclopedia entry for all spiders. It should be replaced with a quote from The Hobbit or Lord of the Rings (or Harry Potter and the Chamber of Secrets) which involve actual giant spiders.

Giant spiders grudge killer bees.

When the player kills a giant spider with an elven dagger and Sting has not yet been created, the dagger is converted into Sting automatically. Sting is made of rustproof steel, instead of wood (this would be tricky to do because of base items; you would still want to be able to create it by naming an elven dagger, but Sting in the lore is made of steel or at least metal, not wood). Sting has bonuses versus spiders, in addition to its bonuses against orcs.

The scroll and spellbook of web allow you to fire a web projectile (which would work similarly to a venom projectile, probably also being in VENOM_CLASS) or beam in a direction. If it hits a wall, it creates a web on the last non-wall space; if it hits a monster it creates a web on the monster’s space and immediately entangles it. If it goes far enough without hitting anything, it creates a web at the end of its range.

Giant spiders should possibly also be able to shoot a web like this, and if so the player should be able to do it via #monster when polymorphed into one.

New artifact The Phial of Galadriel. It is a potion of water (potion of starlight in dNetHack) that acts as an infinite light source which scares giant spiders and Nazgul that come into it, and can be invoked to bless 1 item. May need more powers to make it better, and behavior for what happens when you drink it, but these are unspecified.