Speculative TherizinosaurDigital ArtExobio
From Exobio:Speculative male Therizinosaur display used as a mating show to attract females as well as to intimidate rival males. The Therizinosaur will inflate the neck pouch, much like modern day frigate bird, while “singing” deep grunting sounds to his potential mate. Once he has her full attention he will begin to shake his flamboyant crest and “clap” his massive claws together, creating a loud clacking noise. While this display is considered sexy by the females, it can be very frightening to younger males or overconfident predators.
 

Speculative Therizinosaur
Digital Art
Exobio

From Exobio:
Speculative male Therizinosaur display used as a mating show to attract females as well as to intimidate rival males. The Therizinosaur will inflate the neck pouch, much like modern day frigate bird, while “singing” deep grunting sounds to his potential mate. Once he has her full attention he will begin to shake his flamboyant crest and “clap” his massive claws together, creating a loud clacking noise. While this display is considered sexy by the females, it can be very frightening to younger males or overconfident predators.