Many crustaceans have teeth inside their stomachs but ghost crabs are the first to be found to use them for making a growling sound for warning off threats
Source:
https://www.newscientist.com/article/2215997-ghost-crabs-use-teeth-in-their-stomach-to-growl-at-their-enemies/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home