When a werewolf's bite lands on a hill giant or an ettin, the result is a towering werebeast that hits twice as hard and can snatch a halfling up for an easy bite.
Giant lycanthropes are oversized versions of ordinary werecreatures, created when a smaller lycanthrope attacks a giant. Nearly all are infected or cursed rather than true lycanthropes, so they answer to the moon like any other infected victim. The statistics given apply to the hybrid shape; in giant form they use the normal numbers for their giant type, and in animal form (if they have one) they follow the giant mammal rules for that beast.
Not every giant can catch the curse. Susceptible types are generally giant-kin, the smaller, more human-like giants, with 15 Hit Dice as the dividing line. Within that limit almost any pairing is possible, from firbolg wererats to wood giant seawolves.
Cyclopskin can contract every kind of lycanthropy and match the standard werecreature statistics exactly. True cyclopes nearly always catch bear or bat lycanthropy from creatures that share their caves; other kinds are rare, and fox, tiger, seawolf and exotic types are impossible. Both keep their single eye in every form, without penalty. A cyclops werebat has no giant animal form and cannot fly as a hybrid, but its wings let it glide from a height. Cyclops herders expel the afflicted, who prey on their flocks, so most are outcasts.
Desert giants are immune, since the slow petrifying curse they already bear seems to override it; one freed of that curse might become vulnerable, to what extent no one knows. Fomorians, with their jumbled bodies, have never caught it, nor have fog giants, perhaps because of their Huge (24 feet and up) size or kinship with the immune cloud giants. Stone giants, though under 15 Hit Dice, are too solid and are fully immune.
Ettins can catch only wolf, rat or boar lycanthropy and never gain a full animal form, since their two heads limit how far the body can change. Both heads bite, so a werecreature ettin with a bite gets two per round, each able to infect. In 10% of cases only one head is afflicted; it takes over the body, and the other (usually the weaker personality) is often as frightened as the ettin's victims.
Firbolgs, being very human in build, are highly vulnerable to every type but raven and gain all forms and powers of the type. Their communities pity an infected member and pool resources to find a cure. Verbeeg are just as susceptible (again excepting raven) but react with violence, hunting down and killing the afflicted in their own tribe. Hill giants catch most kinds except raven, most often wolf, boar, rat or bat, and their bulky awkwardness costs them -2 movement in hybrid and animal forms.
Frost giants live where only bear and seawolf lycanthropes survive, and they are prone to both. Frost giant seawolves are infamous terrors of the northern ice-choked seas, and sailors avoid putting out under a full moon. Their werebears become giant white polar bears, and frost giants are one of only two giant kinds with true lycanthropes, the polarweres described under Giant Werebear. Jungle giants catch whatever lycanthropy lives nearby, especially fox, tiger, bat, leopard, cheetah and other cats; feline forms rate as Rare among them and appear twice as often as any other. Their slim builds suit cat forms but weaken hybrids, which lose 2 Hit Dice. Wood giants share the elves' vulnerability to all types and are the other giant race with true lycanthropes, the giant werebats.
A giant lycanthrope uses the same attacks as its smaller kin but deals double damage. Size also gives it new options. A Huge werecreature can give up a claw attack to grab a Small target, which deals no damage but lets it bite the captive automatically next round with no attack roll. Breaking loose takes a successful Bend Bars/Lift Gates roll by the Small victim. The grab also works on Medium creatures, but the giant must hold the target in both hands to get the free bite.
The usual cures apply, adjusted for size: a giant must eat far more belladonna, within 24 hours of infection, than a human would. Giants of 10 or more Hit Dice also get a 5% chance each full moon to fight off the change as it begins and cure themselves. Those who manage it usually keep a trace of the beast, such as extra hair or an animal cast to the features, much like a true lycanthrope's subtle signs.
More: Monsters starting with W · Dragon Magazine monsters · All monsters A-Z
Related: Giant Werebat [Lycanthrope] · Giant Werebear [Lycanthrope] · Kesrin [Unique Weretiger] · Loup de Noir [Lycanthrope] · Loup-garou [Lycanthrope] · Lycanthrope Overview · Lythari [Lycanthrope] · Rat King [Lycanthrope] · Seawolf [Lycanthrope] · Werealligator [Lycanthrope] · Werebaboon [Lycanthrope] · Werebadger [Lycanthrope]