The spider boss is a huge spider (obviously) it could be in a cave with a new block called webbed cobblestone and webbed stone bricks and a bunch of cobwebs. The boss can shoot webs at you for a attack that make you stuck on a wall, ceiling or on the ground for a few seconds. If there is no ground, make the player be stuck in a web for a few seconds. It can also have a chance to poison you with its bite attack. It can also spawn all spiders in the game to attack you.