Are you a shepherd, tired of losing sheep to pesky predators? Sounds like you need a fainting goat! Because of a neuromuscular condition called myotonia congenita, fainting goats go stiff ("faint") when startled or excited. ("Premium fainters" can even fall over on their backs, legs sticking up in the air.) In the event of an attack on your flock, the fainting goat would be a sort of (excuse the pun) sacrificial lamb for predators -- a briefly catatonic goat making an easier meal than a fleeing sheep. Although the condition is not a true "faint" -- the goats are conscious the entire time -- it's a strangely endearing trait.
Fainting goats have gotten a lot of play on the web. Here's a YouTube clip of a news story on fainting goats: