In the London production and some others, he is identified as "Quaxo, also called Mistoffelees", where his identity as The Magical Mister Mistoffelees remains a secret until his song.
In the song "Magical Mister Mistoffelees", he is described as being a rather mysterious, clever and cunning conjuring cat, often found being mischievous or performing amusing antics.
In some productions of Cats, he is portrayed as a kitten and is young, still exploring his magical powers and not yet confident in himself.
According to film actor, Jacob Brent, "He's a bit of a rascal...A child prodigy of the tribe, brilliant in what he does but a little wacky at the same time. He's not an adult yet, but he's not a kitten, so he's at that in between stage...He has these magical powers, he doesn't quite know how to use them yet. But, he's learning."
- "Excellent dancer/singer with fully-trained ballet background - good turns in 2nd. Baritone. Excellent performer and not too tall."
Mistoffelees is a principal role and maintains most of the same attributes as Eliot's original character, but is much flashier.
He has his own song and an extended dance solo in the second act. In most productions he sings the Invitation to the Jellicle Ball. In the original London Cast, Mistoffelees also sang The Old Gumbie Cat, and in the original Broadway production, he sang Mungojerrie and Rumpleteazer.
He and Victoria dance to invite the audience to the Jellicle Ball.
In some versions of the musical, he is given a second name, 'Quaxo'. Often his "chorus" version is known as Quaxo, and his special song costume is known as Mistoffelees.
Mistoffelees performs the most difficult choreography in the show, including 24 fouettés en tournant and dancers cast in the role generally have extensive ballet and gymnastic experience. Because the role's technical demands necessarily trump the performer's vocal abilities, the show permits multiple vocal tracks for the character—thereby allowing some dancers to sing quite a bit, while others do no singing at all.
Mistoffelees is a black and white tuxedo cat. Though the original poem and his song describe him as black "from the ears to the tip of his tail" he is portrayed as black and white due to the technical limitations of stage lighting.
He typically has a fluffy, white bib with the suggestion of a bow tie/collar. For his featured number, he changes into a black velvet outfit covered in crystals with a jacket wired with flashing lights.
His tuxedo markings suggest a classic stage costume for a magician or conjurer performing tricks.
"Quaxo" is the name that Mistoffelees goes by while "incognito", prior to his number. In the original production, a prominent feature of Wayne Sleep's role, besides Mistoffelees' solo, was his tap-dance solo in Gumbie Cat. In some early productions, including those based on the Vienna Production, the name became attached to the tap-dancing beetle, regardless of whether it was played by Mistoffelees.  Quaxo has also occasionally been an ensemble character in his own right, or the name used for a Swing Cat.
SongEditThe song "Magical Mr. Mistoffelees" is performed by Rum Tum Tugger in an attempt to convince the Jellicles of Mistoffelees's magical prowess as a viable option for returning Old Deuteronomy. By the end of the song, the tribe is convinced of his powers, and he conjures up Old Deuteronomy to bring him back from Macavity's clutches.
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