From A Wiki of Ice and Fire
A phantom tortoise is a type of tortoise found in Qarth.
A Clash of Kings
Following the destruction of the House of the Undying, Xaro Xhoan Daxos reports that phantom tortoises have been seen carrying messages between the windowless houses of Warlock's Way.
- ↑ 1.0 1.1 A Clash of Kings, Chapter 63, Daenerys V.