Answer:
The ropes are intended to hold and stretch to death the individual who lay down on the waterbed.
Step-by-step explanation:
The question presented above refers to "The Lightning Thief" written by Rick Riordan, where we are introduced to Percy Jackson a boy who is Poseidon's son with a human, becoming a demigod. Percy is accused of stealing one of Zeus' lightning bolts and needs, along with his friends, to find a way to prove his innocence.
While reading this story, we are introduced to a character named Crusty, who owns a waterbed shop. Crusty, in fact, is a cruel and dishonest sorcerer, who tricks customers into trying out the waterbeds. When customers get down on waterbeds, Crusty shouts the word "Ergo," which causes huge ropes to come out from under the waterbed, trap customers and stretch them to death.