Trasha is a British seller of old fish who acts, talks, & sounds exactly like a real Grouch. Trasha appears in an episode of Sesame Street in a spoof of My Fair Lady with Oscar the Grouch & his girlfriend Grundgetta. In that spoof skit she tries to teach Grundgetta to say the phrase "Fish! Old fish!" with a Cockney accent.
Grundgetta doesn't get it at the beginning & she says Trasha must've been born sounding the way that she does now. Trasha is shocked & says that she wasn't born the grouchy seller of old fish that Oscar & Grundgetta are looking at. She admits she used to be nice, sweet, & cute, which completely grosses the Grouches out. But then she tells them the story of the day she started taking lessons from the legendary Professor Piggins on how to sound like him, which she eventually succeeded at. Grundgetta tries 1 more time & she sounds just like Trasha on her very next try! (Trasha: "I think she got it!" Grundgetta: "Old fish!" Trasha: "By George she's got it!" Oscar: "Wow!")