Since we have enraged zombies, skeletons, and creepers, why not enraged spiders? They can have the same things that the creepers, skeletons, and zombies have, on fire, boosted health, drops shiny string, diamonds, or shiny spider eyes.
Maybe not an Enraged Spider but a Mother Spider? I am guessing it would be a boss and it would spawn babby cave spiders. ( its children ) Like The Mother calls for its children
Please No. Spiders are bad already with the climbing and jumping and getting through 1 block tall gaps. Cave spider poison, etc. Other enraged mobs are better IMO.