Spiders and Fiats

Moment of truth. Arachne wriggled, trying to back up. The woven tunnel contracted around her and held her fast. She tried to wriggle forward, but the trap was already stuck to her abdomen. She couldn't get through that way either. Annabeth had been afraid the spider's barbed legs might puncture the silk, but Arachne's legs were pressed so tightly against her body she could barely move them.
"What — what is this?" she called. "I am stuck!"
"Ah," Annabeth said. "I forgot to tell you. This piece of art is called Chinese Handcuffs. At least, it's a larger variation on that idea. I call it Chinese Spidercuffs."
"Treachery!" Arachne thrashed and rolled and squirmed, but the trap held her tight…
ANNABETH HAD SEEN SOME STRANGE THINGS BEFORE, but she'd never seen it rain cars.
As the roof of the cavern collapsed, sunlight blinded her. She got the briefest glimpse of the Argo //hovering above. It must have used its ballistae to blast a hole straight through the ground.
Chunks of asphalt as big as garage doors tumbled down, along with six or seven Italian cars. One would've crushed the Athena Parthenos, but the statue's glowing aura acted like a force field, and the car bounced off. Unfortunately, it fell straight toward Annabeth.
She jumped to one side, twisting her bad foot. A wave of agony almost made her pass out, but she flipped on her back in time to see a bright red Fiat 500 slam into Arachne's silk trap, punching through the cavern floor and disappearing with the Chinese Spidercuffs.
As Arachne fell, she screamed like a freight train on a collision course; but her wailing rapidly faded. All around Annabeth, more chunks of debris slammed through the floor, riddling it with holes…

Apparently Percy didn't realize what Hazel meant either. Then something yanked Annabeth backward and dragged her toward the pit. Percy lunged. He grabbed her arm, but the momentum carried him along as well.
"Help them!" Hazel yelled.
Annabeth glimpsed Nico hobbling in their direction, Hazel trying to disentangle her cavalry sword from the rope ladder. Their other friends were still focused on the statue, and Hazel's cry was lost in the general shouting and the rumbling of the cavern.
Annabeth sobbed as she hit the edge of the pit. Her legs went over the side. Too late, she realized what was happening: she was tangled in the spider silk. She should have cut it away immediately. She had thought it was just loose line, but with the entire floor covered in cobwebs, she hadn't noticed that one of the strands was wrapped around her foot — and the other end went straight into the pit. It was attached to something heavy down in the darkness, something that was pulling her in.

No," Percy muttered, light dawning in his eyes. "My sword. . ."
But he couldn't reach Riptide without letting go of Annabeth's arm, and Annabeth's strength was gone. She slipped over the edge. Percy fell with her.
Her body slammed into something. She must have blacked out briefly from the pain. When she could see again, she realized that she'd fallen partway into the pit and was dangling over the void.
Percy had managed to grab a ledge about fifteen feet below the top of the chasm. He was holding on with one hand, gripping Annabeth's wrist with the other, but the pull on her leg was much too strong.
No escape, said a voice in the darkness below. I go to Tartarus, and you will come too.
Annabeth wasn't sure if she actually heard Arachne's voice or if it was just in her mind.
The pit shook. Percy was the only thing keeping her from falling. He was barely holding on to a ledge the size of a bookshelf.

Annabeth's leg felt like it was pulling free of her body. Pain washed everything in red. The force of the Underworld tugged at her like dark gravity. She didn't have the strength to fight. She knew she was too far down to be saved.
"Percy, let me go," she croaked. "You can't pull me up."
His face was white with effort. She could see in his eyes that he knew it was hopeless.
"Never," he said. He looked up at Nico, fifteen feet above. "The other side, Nico! We'll see you there. Understand?"

He pointed downstream.
A hundred feet away, a familiar-looking baby-blue Italian car had crashed headfirst into the sand. It looked just like the Fiat that had smashed into Arachne and sent her plummeting into the pit.
Annabeth hoped she was wrong, but how many Italian sports cars could there be in Tartarus?
Part of her didn’t want to go anywhere near it, but she had to find out. She gripped Percy’s hand, and they stumbled toward the wreckage. One of the car’s tires had come off and was floating in a backwater eddy of the Cocytus. The Fiat’s windows had shattered, sending brighter glass like frosting across the dark beach. Under the crushed hood lay the tattered, glistening remains of a giant silk cocoon—the trap that Annabeth had tricked Arachne into weaving. It was unmistakably empty. Slash marks in the sand made a trail downriver...as if something heavy, with multiple legs, had scuttled into the darkness.

MoA ch.50/51 and HoH ch.6