Griffins are sacred animals to Horus, having historically pulled his chariot into battle. Due to following the Path of Horus, Carter possesses the ability to command griffins due to their status as Horus' sacred animals. This ability grants Carter the griffin Freak as his pet and main mode of transport.
Griffins have reddish-gold fur and are twice the size of a normal lion. Their tails serve as weapons, as they are hard and strong enough to easily breaks stones and are covered in dagger-like feathers. Wings stand straight up on their backs and when they move their wings, they beat so fast that they are only a blur, not unlike a hummingbird. Griffins can also travel through the Duat as seen when Freak transported Carter's team back from the Dallas Museum in that way.
At the Brooklyn Museum, a stone griffin is displayed in the Egyptian exhibit that comes to life when Sadie grabs the first section Book of Ra and activates every reservoir of magic in the room, including the griffin and seven bau. During the chaos that follows, the griffin, who Carter Kane names Freak, eats one of the bau. Carter inadvertently discovers that as a follower of the Path of Horus, he possesses the ability to command griffins, Horus' sacred animals. Carter is able to use this to tame Freak who Carter's team uses as an escape route from the Museum as the police approach. Afterwards, Freak remains at Brooklyn House as Carter's pet, participating in the Battle of Brooklyn House.
Throughout the book, Freak the griffin serves as Brooklyn House's main mode of transport due to the unreliability of portals with the rising of Apophis. Freak transports the group to and from the Dallas Museum and to the First Nome for the final battle. At the end of the book, Freak carries Carter and Zia to their first date at the Mall of America and sits on the roof eating frozen turkeys.