That's nothing - some of the Queen albums I have, some funny credits there:
On "A Night At The Opera":
Freddie Mercury - vocals, vocals, Bechstein debauchery and more vocals
And on "A Day At The Races":
Freddie Mercury: vocals, piano, choirmeister, tantrums
Brian May: Guitar, vocals, leader of the orchestra (a "guitar orchestration" on one song)
And something on Roger Taylor's "Fun In Space" album, I can't remember, I'll look it up this weekend. Watch this space . . .
The difference between genius and insanity is merely the difference between success and failure.