Thunder Bluff Banner
Sold by Doru Thunderhorn. Following was observed: 1. Undercity Banner de-spawned by itself after 3mins + ~5 secs from first cast.
The 
Thunder Bluff Banner is a toy purchased from a vendor in Icecrown that lets you plant a Thunder Bluff banner on the ground anywhere in the world.
Guide awaiting review
Find Doru Thunderhorn
Travel to Icecrown and find Doru Thunderhorn at 76.2, 24.4 to purchase the Thunder Bluff Banner.
Purchase the Banner
Buy the Thunder Bluff Banner from Doru Thunderhorn using Champion's Seals as currency.
Tips
The banner has a 3-minute cooldown and lasts for 3 minutes before fading, and it has no cast time so you can place it while moving.
Adding this toy to your Toy Box has been reported to also grant credit for the
Gnomeregan Banner simultaneously, increasing your Toy Box count by two.See the video guide for a full walkthrough of obtaining this toy.
