"No one knows if he meant to be the weirdest wizard of the ages or if it just came naturally."
-- Famous Wizard Card (FW)
Uric the Oddball was a medieval wizard famous for his weirdness
Uric the Oddball's highly eccentric behaviour included: convincing himself he was a ghost, wearing a jellyfish for a hat and, at one point, listening to Fwooper song for three months straight (FB, FW).
Uric the Oddball was sorted into Ravenclaw House at Hogwarts and they are proud of his notoriety. He is also the subject of many wizarding joke punchlines (Pm) and, despite seemingly never doing anything of particular importance, he was covered in first-years’ History of Magic classes (PS8).
Ability to talk himself into thinking or doing anything, no matter how strange or unbelievable
Other canon notes and references
"Wizard of the Month" for September 2004 (JKR)
Uric means "of or relating to urine", and could be a phonetic joke on the name Yorick from the Shakespeare play "Hamlet."