Anomalocaris

The largest beast of the famous ancient fossil beds, anomalocaris looks at first like a giant squid sporting curved walrus tusks. Those 'tusks' are actually tentacle-like limbs bristling with smaller grasping arms, and its tail fins are far longer and wider than any squid's. It is a powerful swimmer that chases down its prey.

It grabs prey with its grasping limbs, constricting for 1d8 with each, then crams the victim into its round mouth for a 2d8 bite. It uses the usual swallowing rules, but rescuers need not worry much about hitting the victim, because he will not last. Unless he breaks out at once (a Strength check with a -2 penalty, or in the companion science-fiction rules a Fitness roll with a -10 penalty), he finds rank after rank of crushing teeth running back through the front of the gut, taking 2d8 bite damage for three turns before digestive juices start in at 1d8 per turn.

Its leathery hide is tough as well; in the science-fiction rules every attack against it loses 2 points of damage and 1 lethality rating. Many weapons also work poorly against a foe that never leaves the water, and almost everyone fighting it ends up swimming sooner or later, since it can easily capsize a small boat big enough for a full infantry squad or a typical adventuring party.