Clam, Giant (variant)

Giant clams are huge, mostly immobile bivalves. An average specimen measures 6' high and over 3' wide. The shell is vertically symmetrical, chalk white in color, and several inches thick.

Combat: Giant clams do not attack per se; rather, they possess an instinctive defense mechanism that can be dangerous to the unwary. Lining the lips of the bivalve are numerous, hairlike cilia that are extremely sensitive to pressure. When touched, they cause the clam to slam shut with great speed and force. Anything struck by the two shell halves (make a normal attack roll) takes 2-12 hp crushing damage. Moreover, a character must make a Dexterity check or have a limb trapped. Trapped characters take 2 hp damage per round until they are successfully freed. A character may attempt to get free by making a successful bend bars/lift gates check; if this is done, no other action can be taken that round. Up to four other people may attempt to help free a trapped character. For each additional person helping, add that person's bend bars/lift gates roll to the trapped character's chance to win free. The chance of opening a clam is doubled if a person uses a spear, sword, or similar item to gain leverage.

Alternatively, a character may be freed by killing the clam. This is, however, no easy task. The exterior of the clam is so thick and hard (AC 0) that piercing weapons do but 1 hp damage, plus any Strength and magical modifiers. Slashing weapons do half damage, while blunt weapons do full damage. The interior of the clam is relatively vulnerable (AC 7) but can be attacked only by missile weapons or weapons over 4' long, and then only if the clam is at least partially open. Note that a clam held open because it is gripping someone's limb is considered to be partially open. If a campaign uses the alternative critical-hit or called-shot rules, a character may sever the muscles that bind the clam shut without killing it.

Habitat/Society: Giant clams are typically found in the vicinity of hydrothermal vents, although they may very rarely be encountered in other parts of the ocean. Now and then, treasure items can be found on or near a giant clam, having been left by an unfortunate trespasser.

Giant clams reproduce sexually. The female lays hundreds of thousands of eggs into the water where they are fertilized by the male's sperm. The fry hatch in 3-4 weeks, moving about slowly (MV 1) by means of undulating cilia.

Ecology: Giant clams are suspension feeders. Those growing around hydrothermal vents live in a symbiotic relationship with bacteria that convert suspended mineral particles into food. Those living in other areas feed on suspended organic matter. Giant clams, both as fry and in their mature state, are a source of food for many of the sea’s creatures. Deep-dwelling octopi have been known to use their shells as lairs.

Giant oyster: A relative of the giant clam, the giant oyster has a grayish color, a more elongated shape, and a more uneven exterior, but otherwise conforms to the previous statistics. Additionally, there is a 5% chance that a giant oyster contains a giant pearl. The value of these pearls is most commonly about 1,000 gp each, but exceptionally large, flawless specimens are worth more than 10,000 gp.

by Bryan K. Bernstein