Wubba is the cornerstone in Sesame Street monster language. Though used frequently throughout the show's history, its exact translation in monster is unknown. Former head writer Norman Stiles states, "It's what monsters say." It is known, however, that repeating the word while hopping up and down does not activate a computer or open a closed phone booth.
Since then, the word has been used for various monster activities, including the "Wubba Wubba Boing Boing" game (episode 3663) and as the repeated chorus of Grover's music video "Monster in the Mirror."
The word transcends the New York City radius of monsters and is heard in England at The Furchester Hotel, where Phoebe Furchester-Fuzz includes the word in her catchphrase ("Fuzza-wubba!"). It is also a favourite word of Pheobe's great-grandmother who, during her own time running the hotel, used to "welcome" guests by jumping up from under the reception desk and shouting it at them (Episode 233: Great Grandma). The word has since proven to be popular with not just monsters, but cheeses as well, as one particular slice appearing in episode 4523 claims to enjoy saying the word.