Hammer Head 6-8 inches long!!!!

[TheRealBigAL]

They are sweeper tentacles That are mostly used for defense purposes as they can be unleashed in an effort to keep another coral from competing for available space. Sweeper tentacles can easily be 3-4 times long as the rest of the tentacles. Built to kill, they typically cary a higher number of cnidocytes (toxin). So make sure the sweepers cannot reach any other corals in your aquarium