This whitish-gray amoeboid creature has bits of flotsam embedded in its amorphous form, which moves inexorably against the current.
Sea Scourge CR 6
Speed 10 ft., climb 10 ft., swim 20 ft.
Melee 2 slams +12 (1d6+7 plus 1d4 acid and grab)
Space 10 ft.; Reach 10 ft.
Special Attacks acid jet, constrict (1d6+7 plus 1d4 acid), engulf (DC 21, 1d6 acid and paralysis)
Once every 1d4 rounds as a standard action, a sea scourge can shoot a stream of acidic juices in a 30-foot line, dealing 2d8 points of acid damage to any creatures in the area (DC 18 Reflex save for half damage). The save DC is Constitution-based.
Coldwater Scourge (+0 CR): The coldwater scourge is a menace to merchant ships and war galleons alike. A coldwater scourge is immune to cold damage, and creatures that fail their Reflex saves versus the scourge’s acid jet are also staggered for 1 round.
Steaming Scourge (+1 CR): A steaming scourge possesses additional Hit Dice and the heat universal monster ability, and emits so much energy that any water in a 10-foot-radius spread around it begins to boil, dealing 1d6 points of damage to creatures that begin their turn submerged in it.
Environment warm oceans
Organization solitary, swarm (2–5), or bloom (6–9)
On watch at night in warm seas, wise sailors are especially vigilant for the hated sea scourge, an ooze that has adapted itself so well to its maritime habitat as to become a significant hazard to native oceanic creatures as well as to humanoid seafarers. While its typical diet consists of sea turtles, dugongs, and other aquatic prey, the sea scourge will feed on whatever creatures it can manage to get a hold of, and is known to prey on humanoids both in shallow waters and at sea, even going so far as to board seagoing vessels. A sea scourge’s acid is capable of dissolving wood in addition to flesh and bone, making it a particularly dangerous threat to most boats. Though it can swim beneath the waves indefinitely, a sea scourge more often tends to search the surface of the ocean for prey, camouflaged as a large clump of ambergris or other seaborne excretion.