The mixed metaphor has long been vilified by language lovers. After all, a metaphor per se is often a stretch. The attempt to combine two or more vastly dissimilar figures of speech usually result in a jarring incongruity and an absurd image. Such clashes are often amusing, although the humor is strictly unintentional.
""Ironing the Bugs Out": Mixed Metaphors,"
Word Ways: Vol. 34
, Article 21.
Available at: http://digitalcommons.butler.edu/wordways/vol34/iss3/21