Simplify the following text for a Grade 9 native English-speaking person.
Original: Achillobator ( ; `` Achilles ' warrior\/hero '' ) is a genus of dromaeosaurid theropod dinosaur from the late Cretaceous Period of what is now Mongolia , about 90 million years ago .
Simplified: Achillobator is a dromaeosaurid theropod dinosaur from the Late Cretaceous Period of what is now Mongolia . It lived about 90 million years ago .