Monster Monday: Xiphactinus, Prehistoric Monster Fish

Today's Monster Monday is xiphactinus, a giant prehistoric monster fish known for swallowing other large fish whole. These ugly fish reached lengths of 15 to 20 feet and swam the seas of the Late Cretaceous, when Tyrannosaurus was roaming the land.

Xiphactinus audax life restoration by ДиБгд, via Wikimedia

It's no secret that I am a fan of prehistoric sea life. Xiphactinus may not be as well-known as, say, ichthyosaurus, but its fossils certainly leave an impression. Not only are they big and mean looking, with those upturned, toothy maws, but they often show another pretty big fish trapped within the fossil ribs of the xiphactinus. Of course it can swallow an adventurer whole. And we know they didn't just settle for prey "small" enough to swallow - a 20 ft. xiphactinus fossil found in Canada in 2010 had the flipper of a mosasaur in its jaws.

photo by Spacini, via Wikimedia

Xiphactinus audax with a delicious Gillicus arcuatus in its stomach.
Fossils on display at the Sternberg Museum of Natural History in Hays, Kansas

This also marks d20 Despot's first monster that starts with an 'X'. My patrons on Patreon know that it won't be the last: coming up fairly soon, we have another 'X' monster, this one from Aztec mythology.

The following text in gold is available as Open Game Content under the OGL. Open Game Content is ©2018 Jonah Bomgaars.
This 20 foot fish has a gaping, upward-turned maw lined with protruding teeth

Fish, Xiphactinus            CR 3

XP 800

N Large animal (aquatic)

Init +6; Senses low-light vision, scent; Perception +8

DEFENSE

AC 14, touch 11, flat-footed 12 (+2 Dex, +3 natural, -1 size)

hp 30 (4d8+12)

Fort +7, Ref +6, Will +2

OFFENSE

Speed 50 ft.

Melee bite +7 (2d6+7 plus grab)

Space 10 ft.; Reach 5 ft.

Special Attacks fast swallow, swallow whole (2d6 bludgeoning damage, AC 11, 3 hp)

STATISTICS

Str 20, Dex 14, Con 17, Int 1, Wis 12, Cha 2

Base Atk +3; CMB +9 (+13 grapple); CMD 21

Feats Improved Initiative, Skill Focus (Perception)

Skills Perception +8, Stealth +6, Swim +17; Racial Modifiers +4 Stealth

ECOLOGY

Environment any ocean

Organization solitary

Treasure none

This primordial fish regularly reaches lengths of fifteen to twenty feet. It’s large mouth and thick body let it easily swallow prey over six feet long.

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Plot Hooks and Encounter Ideas

• The storm surge from a recent hurricane stranded a massive xiphactinus in a shallow lagoon, and it has been terrorizing the halfling fishing village on the lagoon's shores.
• A toothy fish bit a valuable magic ring off the hand of a swimming nobleman, who then saw the fish swallowed whole by a xiphactinus. The newly nine-fingered nobleman has put up a reward for whoever can kill the xiphactinus and locate the ring within the belly of the smaller fish within the belly of the bigger fish.
• The miners were used to finding strange fossils that looked like fish bones while they were digging for valuable minerals, but recently there have been sightings of a giant fossil fish skeleton swimming through the air of the deep tunnels as if they were filled with water, and some miners have started to go missing.

-your ichthyodectid d20 despot