Explanation: Prodded by requests from skeptical fans, MythBusters Tory Belleci and Kari Byron set out to investigate whether a certain breed of goats called Tennessee fainting goats can be literally scared stiff and fall over. These goats, which became famous from viral videos on the Internet and subsequent news stories, supposedly seize up and faint when sufficiently startled.
Tory and Kari's field trip to a fainting-goat ranch verified that the lock-kneed livestock indeed exists. Tennessee fainting goats are born with a condition called myotonia congenita, which causes their leg muscles to tense up as part of the fight-or-flight response.
Their name is a little misleading, however, since the goats don't actually lose consciousness. Unable to move their legs, the terrified goats can't run anywhere and just topple over. So by sneaking up and surprising the unsuspecting animals in the field, the MythBusters induced enough four-legged faints to confirm the myth.