Drosselmeyer is the mysterious magician-like figure in Tchaikovsky's ballet "The Nutcracker". Called affectionately "Uncle Drosselmeyer", he is the godfather of Clara, the heroine of the ballet (or Marie, as she is called in some productions; Masha in others.) It is never explained in the ballet where he comes from or why Drosselmeyer has magical powers, but one of them, apparently, is the ability to bring toys to life. He sets the entire plot of "The Nutcracker" in motion by giving Clara the toy on Christmas Eve. Clara is especially fond of him (though their relationship is not borderline romantic, as some who see the ballet believe). Drosselmeyer seems to be aware of things of which the other characters are not; for instance, in the Baryshnikov production of the ballet, as well as Peter Wright's Royal Ballet production, only he seems to know that the Nutcracker must fight the Mouse King, and that with the Mouse King's death the Nutcracker will become a handsome Prince. And it is Drosselmeyer who, at the end of the dream in the Baryshnikov "Nutcracker", returns to bring Clara back to the real world.
In the 1986 Pacific Northwest Ballet film "Nutcracker", featuring sets and costumes by Maurice Sendak, Drosselmeyer (here spelled "Drosselmeier") comes across as much more frightening. Clara is notably uneasy around him at the Christmas party, much, much more so than she is in most other versions, and this makes the relationship between the two in the film that much creepier, giving him a "dirty old man" quality, especially when he turns up in Clara's dream as a pasha in a harem, jealous of Clara's relationship with the Prince.
In George Balanchine's production of "The Nutcracker", filmed in 1993, Drosselmeyer is mysterious, but kind. He appears on the grandfather clock at midnight, just as in the Baryshnikov "Nutcracker", is not seen again in this production after the toys come to life.
In E.T.A. Hoffmann's 1816 story "The Nutcracker and the Mouse King", on which the 1892 Tchaikovsky ballet is based, the reason for Drosselmeyer's involvement is made clear. He was once Official Ratcatcher for the King and Queen, and set mousetraps for the Mouse Queen and her children. This led to a series of incidents which culminated in Drosselmeyer's nephew being turned into the Nutcracker by a magic spell.
In Peter Wright's adaptation of "The Nutcracker" for the Royal Ballet, the Nutcracker is Drosselmeyer's nephew. His "backstory" is explained at the beginning of the 2001 telecast in scrolling credits.
In Patrice Bart's complete 1999 reworking of "The Nutcracker", Drosselmeyer is played as a young man who helps Clara come to terms with her kidnapping by Russian revolutionaries, an element not found in any other version of the story.
In Mikhail Chemiakin's revisionist version of "The Nutcracker" for the Mariinsky Ballet, first staged in 2001 and released on DVD in 2008, Masha's adventures are not a dream. Drosselmeyer is depicted as not only potentially sinister, but as a physically uglier figure than usual, resembling the vampire Nosferatu. He appears to be in league with a new character, the Rat Cardinal, and subtly manipulates Masha and the Nutcracker Prince's relationship, which is depicted in the Chemiakin version as being more passionately romantic than in previous versions. In this version, their relationship takes a rather gruesome turn - after the couple is married they are turned into a pair of candy dolls, presumably to be eaten in the future by the same mice that attacked the toys earlier.