Claudia appears in the bonus RPG that is included with Professor Layton and the Last Specter. He is found in Clement's Boutique during the day and behind the Vinegar Grill during the night. If the player disturbs his walking pattern, he will hiss.
Claudia is first seen being held by Lady Dahlia when she and Professor Layton meet. As Layton and Dahlia are about to shake hands, a very loud noise shakes the walls of Reinhold Manor, and scares Claudia away. Layton and Luke give chase and find him near the clock tower. Luke attempts to befriend him, only to receive a scratch on the face, and Claudia runs away again. Later, an old woman named Agnes tells them to lure Claudia back with fish bones, and it proves successful. Claudia is seen again later wandering around the manor gardens with Simon's glasses in his mouth shortly after Simon's "death".
This fluffy little cat may have a delicate name, but the shocking truth is that she is actually a he. He usually stays close to Dahlia, but he has been known to slip away and tear up the fish stand to relieve a little stress.