Teacup to gerbil

"'But,' said the Prime Minister breathlessly, watching his teacup chew on the corner of his next speech..."

- The Muggle Prime Minister is stunned by Fudge having turned his teacup into a gerbil.

Teacup to gerbil (incantation unknown) is a Transforming spell that turns teacups into gerbils. Minister for Magic Cornelius Fudge used this spell to prove himself be a wizard to the Prime Minister of Muggles.

Aftermath

 * The Prime Minister was stunned. Despite the evidence of his eyes, he tried for a time to convince himself that Cornelius Fudge was a hallucination. The continued presence of the gerbil was less easily explainable, but he gave it to his niece, in an attempt to rid himself of all reminders of the encounter.

Behind the scenes

 * This spell may be similar in mechanics to Teacup to Rat, which begins with the same object, but features a different type of rodent as the end result.

Appearances

 * Harry Potter and the Half-Blood Prince

Notes and references
Spells of unknown incantation Transforming spells