Form burster
The machine in the old computer room that tore the endless strip of listing paper into separate sheets along the perforations.
Line printers and dot-matrix printers fed continuous form paper as one long, folded web. After printing, the burster broke the web into loose sheets along the perforation lines, faster and straighter than doing it by hand. Many machines also trimmed off the perforated tractor edges down the sides at the same time.
The closely related decollator did the parallel job of separating the carbon layers of multi-part forms. Both machines vanished from ordinary offices once the cut-sheet printer took over, but they survive in print shops and with anyone who mails payslips and invoices by the million.