Xiphactinus audax (and Xiphactinus vetus) were some big scary old fish. Reaching estimated lengths of nearly 20 feet (6m), these fish were truly monsters of the deep ocean. In fact, they simply look as though they would be highly willing to eat, or at least maim, any creature slow, dumb, brazen, or unfortunate enough end up within striking distance of that terrible set of teeth. Stomach contents of these big mean fish are testaments to the amount of horror they imposed upon the oceans of their day; approximately a dozen remains have been discovered with items such as a fish nearly 6 feet long as well as appendages from other larger animals like plesiosaurs, potentially scavenged, have been found with the bones of Xiphactinus specimens. Most of these fish have died with their prey barely digested or even stuck in their gullets, as though the writing prey killed their killer in their death throes. Big and mean and prone to biting off more than it should attempt to swallow. As well known as the stomach contents, and actual fish, are known, there is little to nothing known about Xiphactinus' life cycle. We have evidence of their deaths, as scavenged morsels in the bellies of sharks such as Squalicorax and Cretoxyrhina. Xiphactinus skeletons are well preserved throughout the US at the limits of the Western Interior Seaway and also globally as far from the Western Interior Seaway as the middle of Europe and Australian fossil beds.