Check out this cool vibrating moving robot we made a while ago.
We made it from an old back massager and some baling wire. You take 3 pieces of wire and loop them through the holes in the mounting ring on the motor and then around each other. Curl up the ends of the wires so that they don’t have sharp ends scratching up the floor. Then you take the battery pack and hot glue it on the side. That’s all there is to it.