Hermes Boots

Hermes Boots are an accessory that can be found in Underground and Underground Jungle Chests.

Hermes Boots slightly increase the wearer's movement speed, and provide a large speed boost after running in one direction for about 2 seconds, which lasts for as long as the wearer continues running in that direction without interruption. Interruptions include colliding with an object or taking damage.

Jumping while running will not cancel the speed boost, even if the Cloud in a Bottle, Shiny Red Balloon, and/or Rocket Boots are also used. Falling onto a lower level of blocks will also not interrupt the speed boost. If used along with a Cobalt Shield, you will not lose the speed boost after getting hit by an enemy.

Top speed can be reached quickly with the use of the Grappling Hook or the Ivy Whip. Simply grapple the ground before you (around 5-15 blocks) and then jump as you are getting pulled forward. Another way to instantly use Hermes Boots is to grapple the middle of a door and then open it. Continue running in the direction that you opened the door and you are now running at full speed! :)

Trivia

 * This item has similar functionality to the Pegasus boots from The Legend of Zelda: A Link To the Past
 * Hermes Boots are a reference to "Hermes", the Greek messenger of the Gods, known for his flying boots and incredible speed.