Because of the glitch, that humble car wrench is now so big it could wrench the whole goddamn car. Why? For some reason, the game gets confused whenever a flare is briefly flying around, and when you then pick up a weapon, it dumbly recalculates the height of the weapon to be the same height that the flare was fired at, making weapons like the 2x4 and the hand ax so massive that their names sound like they're supposed to be ironic.
But while the weapons sure looked a lot more intimidating, it's not as if they did any more damage to the unkillable Jason. What did change, however, was their reach, meaning those scared teens could hit their implacable stalker from ridiculously far away. And if you've ever seen a Friday The 13th movie, you know that Jason thinks he's too cool to run. So while he was slowly lumbering toward his victims, those victims could cave his head in with a 40-foot ax long before he could get into stabbing range.