Hammer is a character in the 3 Ninjas film. He is one of Fester's buddies along with Marcus. He and his buddies attempt to assist Mr. Brown and Snyder by kidnapping the young ninjas to cease Sam Douglass and the FBI from taking any further actions against their plans.
Snyder arranges to kidnap the boys. Mr. Brown suggest to him that he knew someone who can help and has help on several prior missions they've had and that he was a relative of his. Snyder tell Mr. Brown to make the call for him and hire his surfer nephew Fester and his friends Hammer and Marcus. During the night they attempt to kidnap the boys, their father comes home with a few of his colleagues which they're forced to withdraw the attempt. The next morning as the boys ride their bicycles to school, Fester and his crew fail to grab them.
The boys are at home with a babysitter when Fester, Marcus and Hammer show up. Fester and his buddies jump on the pizza delivery guy and Fester poses as him in order to have a reason for entry. The kidnappers subdue the babysitter and lock her in a closet. Colt witnesses them subduing their babysitter and their guns and tells his brothers. The boys decide if they can take care of Fester and his gang themselves, then their ninja training would be worthwhile. Using booby traps and their ninjitsu, they weaken the intruders.
After the boys' weaken the intruders, they go to the boys' room and figure out how to lure one of their contacts at which they take captive. The contacted Emily attempting to imitate Rocky's voice, but successfully works with Emily half asleep and less aware. They hold Emily captive at the door. They bring Emily to the door of the study room as captive at gunpoint. Meanwhile, Colt's trick with the instant diarrhea works on Hammer and Marcus leaving Fester alone with Emily. Fester is subdued by Emily while they have gone to the bathrooms, and his buddy Marcus is finished off by Tum Tum.
Rocky and Colt find Hammer still suffering from the diarrhea in their bathroom. Colt opens the door to smell an odor. While Colt is reacting to the odor, Hammer picks up the plunger trying to attack him, but Rocky kicks it out of his hand disarming him. Before attacking Hammer pleads, "Not the stomach, not the stomach!" The boys nod at each other and deliver a double spinning elbow finishing him off. Before falling unconscious, Hammer says, "Thanks." for not hitting him in his stomach and goes unconscious.
Hammer and his buddies were likely aided and made their escape when Mr. Brown and the ninja henchmen eventually came to the house to kidnap the Douglas boys. It is unknown if he and his buddies were eventually arrested after the defeat of Snyder or if they got away.