http://legion.wowhead.com/item=140309/prismatic-bauble - Toy that shows a rainbow behind you. Lasts 20 seconds. Cost: 100k gold.
http://legion.wowhead.com/item=137570/bloodfang-cocoon - Spider mount. Cost: 100k gold.
These items are supposedly sold by the "Mad Merchant", who sells extremely expensive items.
The goldsinks are real. RIP to all that easy money we made with the garrisons.