Joso's Prank is a trading galley owned by Illyrio Mopatis. It has two hundred oars. Its figurehead is made of iron in the shape of a jester's face. It is renamed Meraxes, after the Targaryen dragon of old.
A Clash of Kings
Magister Illyrio Mopatis sends Saduleon, Joso's Prank and Summer Sun to Qarth to bring Daenerys Targaryen back to Pentos in preparation for her return to Westeros. Daenerys accepts, but insists in renaming the ships as Balerion, Meraxes, and Vhagar in homage of the three powerful dragons of Aegon the Conqueror.
A Storm of Swords
The Meraxes is broken up along with the others on the shores near Meereen so that Daenerys's army will have the wood to build rams, shields and other items useful in a siege. They use the mainmast of Meraxes, which they nickname Joso's Cock, to break down the eastern gate of the city during the siege of Meereen.