Clam, Giant
FREQUENCY: Rare
NO. APPEARING: 1-4
ARMOR CLASS: 10/3 (shell)
MOVE: //1”
HIT DICE: 3
% IN LAIR: 100%
TREASURE TYPE: See below
NO. OF ATTACKS: Nil
DAMAGE/ATTACK: Nil
SPECIAL ATTACKS: Entrapment
SPECIAL DEFENSES: Nil
MAGIC RESISTANCE: Standard
INTELLIGENCE: Non-
ALIGNMENT: Neutral
SIZE: M (6’ length)
PSIONIC ABILITY: Nil
Attack/Defense Modes: Nil
LEVEL/X.P. VALUE: III/90 + 3/hp
Clam, Giant, Carnivorous
FREQUENCY: Rare
NO. APPEARING: 1-4
ARMOR CLASS: 10/4 (shell)
MOVE: //1” [10” using bursts]
HIT DICE: 4
% IN LAIR: 50%
TREASURE TYPE: See below
NO. OF ATTACKS: 1 ram
DAMAGE/ATTACK: 1-10
SPECIAL ATTACKS: Poison cloud, surprise, continuous damage
SPECIAL DEFENSES: Nil
MAGIC RESISTANCE: Standard
INTELLIGENCE: Animal
ALIGNMENT: Neutral
SIZE: M (6’ length)
PSIONIC ABILITY: Nil
Attack/Defense Modes: Nil
LEVEL/X.P. VALUE: IV/175 + 4/hp
Both the giant clam and the giant carnivorous clam are found in shallow tropical and semitropical waters, down to a maximum depth of 200’. Both have numerous tiny, blue eye spots located near the edges of the shell. These eye spots can distinguish between light and shadow, and can detect movement, but not size. Special organs near the front of the mantle cavity, where the soft body of the clam sits, detect and analyze chemical traces in the water.
The giant clam is a filtrationist, living on minute shrimp and microscopic animals, and on algae colonies growing inside the clam’s shell mantle. When threatened or when something reaches inside the clam.s shell, the giant clam’s usual defense is to close its shell. Due to the animal.s power ful adductor muscles, which act as a hinge for the shell, a bend bars/lift gates roll is required to force the shell open again.
The giant carnivorous clam has evolved a slightly higher intelligence than its sessile cousin, which it uses to hunt for prey. Both clams are capable of using their inhalent and exhalent siphons to move across the sea bottom; the carnivorous clam can also, through vigorous clapping of its shell halves, .swim. in a jerky fashion with its exhalent siphon, providing lateral adjustment and maneuverability. The shell thickness of the clam is reduced to increase buoyancy. The clam’s external cilia have evolved into a set of 4-10 2’-long tentacles, used mainly to grasp and move prey to the clam’s stomach. The tentacles are too weak to do any damage or to grasp and hold prey with a strength greater than 6.
The carnivorous clam can, by a sudden expulsion of water through closing its shell, jet backwards and ram an opponent within 5’ for 1-10 points of damage. The clam’s usual method of attack is to shoot a mild neurotoxin into the water through its exhalent siphon. The toxin disperses in a 5’-diameter cloud and causes paralysis for 1-12 rounds to any creature that fails to make its saving throw vs. poison. The paralyzed prey is then grasped by the clam’s tentacles and either pulled directly into the clam (for 1 hp/turn digestion damage thereafter) or cut into smaller pieces by sawing motions of the clam’s shell (1-2 hp damage/round).
The inside of both clam shells are lined with nacre or mother-of-pearl, with a base value of 50 gp depending on the amount of mother-of-pearl adventurers can recover. (DMs should consult the table on page 26 of the Dungeon Masters Guide to determine the final amount. This amount should never exceed 500 gp.) There is a 10% chance that a clam has one giant pearl worth 500-1000 gp, depending upon its size and quality. The pearl may be as large as a fist, but will not be as lustrous as smaller pearls from pearl oysters. There is a 5% chance that, scattered about or buried in the sediment around the clam, a few coins, accoutrements, or minor magic items were left behind by an unfortunate victim who was caught and drowned.
Both clams are nearly identical in appearance. The upper shell of both clams is light brown, while the lower shell is white. Giant clams of both varieties are found nestled in the sand or resting on the sedimentary bottom of oceans. Sometimes, the giant clam buries itself to provide an offensive advantage against prey (surprise on 1-5).
Originally appeared in Dragon Magazine #116 (1986).
MCA4 version…
Giant Carnivorous Scallop
The giant carnivorous scallop is, to the uninitiated, virtually indistinguishable from a giant clam. However, it has evolved slightly higher intelligence than its cousin, and actively hunts for prey. This creature can actually swim by making a butterfly movement with its shell. It can, by a sudden expulsion of water, jet backward, ramming an opponent within 30 feet for 1d10 points of damage.
The carnivorous scallop’s usual method of attack is to expel a mild neurotoxin through its exhalant siphon. The toxin disperses in a 10-foot diameter cloud that paralyzes for 1d12 rounds any creature that fails to make a successful save vs. poison. The paralyzed prey is then grasped by the external cilia and either drawn directly into the stomach (where it suffers 1 point per round of damage while being digested) or cut into smaller pieces by sawing motions of the shell (which inflict 1d3 points per round).
Sometimes a giant carnivorous scallop buries itself in a sandy ocean bottom to hide from predators or surprise prey. When the clam is concealed, opponents have a -5 penalty to their surprise rolls.
Other giant clam notes from MCA4…
Some species have wavy-edged shells that are very sharp. On a natural roll of 19 or 20, these will sever a trapped limb.
Larger or smaller giant shellfish can be generated by assuming 1+1 Hit Die per two feet of shell diameter and adjusting other characteristics accordingly. Unconfirmed rumors suggest the possibility of intelligent, or even psionic clam and oyster colonies.
