Mullet

A mullet is a type of fish, and I hope that our esteemed biological categorists will give a better description, including a link to the appropriate genus/family/species.

A mullet is also a type of haircut, long associated with United States redneck culture. Short on top, long (shoulder length or more) in back.

A mullet is slang for a person that mindlessly follows a fad/trend/leader.