The giant crab/crab swarm entry in the Bestiary gestures toward larger crab varieties in a table (and The Daily Bestiary’s entry way back in November 2011 speculated about them as well). But the Bestiary 3 is nice enough to save us the trouble of statting up the shark-eating and shipwrecker crabs ourselves. As with most Advanced species, each has a special ability worth noting (darting and powerful claws, respectively, as well as the usual constriction). But it’s the size and hit points (a Colossal 14d8+126 for shipwrecker crabs) that will really get players’ attentions…
Adventurers become trapped in a cove by shark-eating crabs, only to find they are not alone. A hunting party of adaros became trapped there as well when their shark companions were devoured. The adaros propose teaming up to escape the cove, but as the effort is underway a storm begins brewing, sending the adaros into a rain frenzy.
A kraken returns from a five-year-long vision quest to a rude awakening—ignorant Easterners have colonized his home island. (The local Western and gnome natives have centuries-old taboos against approaching his domain.) Outraged, the leviathan sends shipwrecker crab minions to tear down the Easterners’ wooden palisade fort. Even if the kraken’s hold on the crabs is broken, they will still revert to instinct and merely switch their attention to the ships in the harbor instead.
Not all giant crabs are of the hard-shelled variety. When the skyship Osprey’s Hammer goes down in the shoals, it carries the magical communications rig for the entire Zephyr fleet. Adventurers who go looking for the sunken vessel will find a nasty surprise—it is currently the home of a shipwrecker hermit crab, which wears the entire ship on its back like a giant shell.
—Pathfinder Bestiary 3 60