‘Lunatic’ Asteroid?

“The Earth has only one true Moon, but astronomers have found that we also have a ‘quasi-moon’ – a travelling companion through space that is circling the Earth while actually orbiting the Sun.

The object, the only quasi-moon discovered so far, is an asteroid called 2003 YN107 which circles the Sun in an orbit almost identical to Earth’s, but follows a corkscrew path that from time to time means that it appears to orbit Earth.” —New Scientist