The Spider of Crystal is a minor character from the 1985 animated series She-Ra: Princess of Power.
She-Ra: Princess of Power
The Spider of Crystal was a monster from another world which came to Etheria long ago. An evil magician summoned it to try and conquer his enemies. But he soon found himself unable to control it. The Spider lived only to destroy and it's power was great. The Trolls managed to seal it beneath a great mountain and put a stone mount on top of this mountain to maintain the magic which held the beast.
Shadow Weaver discovered the mountain that held the spider in the Shadow Kingdom of Skull Path and Scorpia used her Crawler tank to clear the entrance which was hidden by rocks. Inside, they found the Spider, greatly reduced in size and balancing on a floating pedestal. Weaver used a spell to free it. As the spider grew to it's original, enormous size, it's rock prison began to crumble and the two Hordeswomen fled.
The Spider of Crystal began to terrorize the Shadow Kingdom and covered a small village entirely in crystal. Agho, King of the Trolls decided to join the battle himself and told She-Ra and her companions that the only way to trap the spider was to trap it in stone. Kowl suggest to lure the monster into a narrow pass. Bow, Grox and Sprag managed to get the Spider's attention, and riding his horse Arrow, Bow lured it into the pass. She-Ra then pushed over the two peaks on either side of the pass to trap it, and Agho used an ancient spell of his Troll forefathers to return the Spider of Crytal to sleep.