From A Wiki of Ice and Fire
Casso, also known as the King of Seals, is the trained pet seal of Tagganaro, a Braavosi dockside entertainer, thief, and cutpurse.
A Feast for Crows
Arya Stark, disguised as the street urchin and fish peddler Cat of the Canals, sells some mussels to Tagganaro, and Casso barks and lets her shake his flipper.
A Dance with Dragons
Arya, disguised as an ugly, disfigured girl, passes by Tagganaro playing with Casso while his cutpurse works the crowd. Tagganaro does not recognize her, though Casso may, as he barks and claps his flippers when he sees her.
- ↑ 1.0 1.1 1.2 A Feast for Crows, Chapter 34, Cat Of The Canals.
- ↑ 2.0 2.1 A Feast for Crows, Appendix.
- ↑ A Dance with Dragons, Chapter 64, The Ugly Little Girl.