That would be the Schildkröt 900 (aka "The Legendary Schildkröt"), but that's best not mentioned, really. Speak not its name, lest ye summon the eldritch horrors from their house of dreams. Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn!
Other contenders would be the BTY Boll TriCarbon, the...