Well, I'll explain the lead pipe even though there's an equal amount of yes/no. It's a version of execution. you press Q for melee. Then you hit someone and immediately press F afterwards. Your Thing Thing should grab the person. Press F once more to execute them by sticking the pipe through their head and twisting it off or bashing their skulls twice, throwing them on the ground, and hitting them once more, causing an explosion of giblets and pieces of head.
Note: You are invulnerable to attack when executing.
Note2: After sticking the head on the pipe, it gains twice as much melee damage until the head explodes.