It was nicknamed the `` Terror Bird '' for obvious reasons : it was one of the largest carnivorous birds ever to have existed , along with Titanis , Kelenken and Brontornis . Its rudimentary wings had claws shaped like a meat hook for tackling prey , which was then killed with the massive beak . It was nicknamed the `` Terror Bird '' for obvious reasons : it was one of the largest carnivorous birds to have ever existed , along with Titanis , Kelenken and Brontornis , and its rudimentary wings formed arm-like structures with claws shaped like a meat hook for tackling prey , which was then killed with the massive beak .