A large load of shit, which is approximately the size and shape of a football. Typically feces and water overflow from the toilet. Side effects include bulging eyes, dizziness, numbness in both legs, profuse sweating, stretch marks, vomiting, abnormal hair growth, erectial disfunction, and a freshly ripped asshole. A McCasky is a death sentence for any public restroom.
Billy dropped a McCasky in the White Castle toilet.
by Hobo Joe Bessinger October 21, 2005