A "category V" Kaiju, Slattern is the biggest and baddest of them all, says del Toro. "I introduce it almost like a building coming out of the water. It is really, really quite gigantic." While his peers have really short necks, Slattern is notable for his extremely long neck and his half-horn, half-crown noggin. "I wanted to give it almost this demonic shape on the head and to make it the most majestic of all the Kaijus."