Stygian Ice

Stygian Ice is a magicial type of ice that is cooled in the River Styx. The Stygian Ice Whistle that Quintus gave to Percy Jackson in The Battle of the Labyrinth was made of of Stygian Ice. The whistle would shatter to pieces once used when it is in an emergency, so he could only use it once, so it is possible that this happens with other Stygian Ice items. Percy has only used it once when he was faced by thousands of monsters in Antaeus' Arena after killing him. Percy uses the Stygian Ice Whistle, and Mrs. O'Leary appears and stampedes the monster-filled stadium, rescuing him, Annabeth, and Rachel Elizabeth Dare.Stygian ice items actualy aren't cool as normal ice and can't be melted.(but it can be shattered as shown by Percy in book 4)