Mondegreens

Mondegreen is a misheard lyric from a song or a poem.  The history of music, popular and otherwise, is rife with examples.

Song: Blowin in the Wind
Artist: Bob Dylan
Lyric: The answer, my friend, is blowin' in the wind
Mondgreen: The ants are my friend, they're blowin' in the wind

Song: O Fortuna (The Lament of Fate, from Carmine Burina)

Artist: Carl Orff (composer and conductor)

Lyric: The lyrics are in Latin, so there are many instances in which words an be misheard in English

Mondegreen: See video below (mildly NSFW)

Song: Purple Haze

Artist: Jimi Hendrix

Lyric: 'Scuse me while I kiss the sky

Mondegreen: 'Scuse me while I kiss this guy

Song: Bad Moon Rising

Artist: Creedence Clearwater Revival

Lyric: There's a bad moon on the rise

Mondegreen: There's a bathroom on the right