oddball
oddball (od"bal`) , noun
1.
A person with an unusual or odd personality; an eccentric person. [informal]
2.
Anything unusual in its class.
Pluto is an oddball among its eight sister planets. It's the smallest in both size and mass, and has the most elliptical orbit. It moves in a plane tilted markedly away from the other planets' orbits. Moreover, Pluto is the only planet made almost entirely of ice.
oddball (od"bal`) , adjective
Eccentric; very unusual; strange; bizarre; as, an oddball request. [informal]