5 foot, 8 inch: World's Biggest Ass

Romulus the Donkey is set to beat the Guinness World Record as the World's Tallest Donkey.
 

Measured by a local vet in Texas, Romulus is an incredible 68 inches tall, 2 inches taller than previous holder Oklahoma Sam. 

Romulus and his twin Remus were rescued by owners Phil and Cara Yellott when their previous owner could not afford to look after them.