Procrustes

Procrustes, also known as Prokoptas or Damastes, was a rogue smith and bandit from Attica. Procrustes was a son of Poseidon with a stronghold on Mount Korydallos, on the sacred way between Athens and Eleusis. There, he had an iron bed in which he invited every passer-by to spend the night, and where he set to work on them with his smith's hammer, to stretch them (or cut them down) to fit. Procrustes continued his reign of terror until he was captured by Theseus, travelling to Athens along the sacred way, who "fitted" Procrustes to his own bed.

The Lightning Thief
Procrustes, who introduces himself as "Crusty", is a monster who appears briefly in The Lightning Thief. He is also called "The Stretcher", due to his unfortunate tendency to tie travelers to two bent pine trees and stretch the victims until they tear in half. He is the owner of a Los Angeles mattress store. For his stretching habit, all of the beds are rigged to snare anyone who lies down on them with ropes and extend them to exactly six feet. If they are over six feet, the excess is removed by Procrustes with a very large battle axe.

Percy, Annabeth, and Grover encounter Procrustes while searching for the gate to the Underworld. He seems to be kind, although frightening in appearance, and invites them to hide from several gang members in his store. The monstrous salesman tricks both Annabeth and Grover to lay on mattresses, thereby trapping them, but Percy remains free and convinces Procrustes to lie down himself. Once the snares have been triggered, Percy releases his friends and cuts Procrustes down to size with Riptide, thereby destroying him.'

Film
In the film, The Lightning Thief, Procrustes' actor was Tim Aas, but he never showed himself. They maybe cut him out before the movie hit the theaters.