A large metal pipe
Kevin McCallister used a large metal pipe as a booby trap at Rob McCallister's Brownstone house. Knowing that Harry Lyme and Marv Murchins would avoid the paint can trap that he used the year before at his house, he hurled the hidden pipe down at the burglars after deploying the cans. The pipe knocked Harry and Marv into the basement before Kevin cut the rope that bound it to the second floor's railing, sending the pipe rolling down the stairs and to the basement with them.[1]