Spider cave

Located underground below the mineshaft and above the stronghold, only appear in wider underground spaces,it's indicated with the cave entrance filled with cobweb, once inside you'll eventually see more cobweb and find a spider egg, mining the egg has the chance to spawn spider (or cave spider) or nothing. Deeper in the caves you'll approach more egg, until you get to the deepest part and meet the Mother spider, it's a bigger version of a spider(or cave spider).She spawn of course in the deepest part the spider cave with higher cave ceiling so she could climb on and a big deep hole that led to more spiders and eggs, the place will be filled with string block which attached on each side of wall, approaching the Mother spider will trigger a boss fight, the player have to fight her on the string block above the deep hole, when hurt enough she will raises her body and will call the other spiders from the deep hole, after that she'll retreat to the cave's highest ceiling and watch your fight, she can help the spiders by spitting cobweb to the players that making them vulnerable, after beaten those spiders, the Mother spider will come down and fight you again, defeating the Mother spider will make her do her last roar that destroy all the spider egg nearby(without spawning the spider) and will drop normal spider loot and Spider fur in a big amount,brew it to make potion that allow player to climb vertically without support or combine it with boots to slightly reduce knockback.