It's still not Friday, but I hope that won't stop you from checking out today's entry. Paizo friend Kajehase brought up this article and asked for an encounter, which is presented below. It's a typical rats-ate-everything-including-themselves-and-now-they-haunt-the-ship-they-infested event, which a GM could extend by allowing the skeletal crewmembers or the rats to curse a victim with cannibalism (rather than the intensified filth fever). The players could follow up with the wizard who created the magic that caused this situation—perhaps there's another such enchanted ship ready to set sail that is basically a time bomb of ravenous rats.
Rat-Infested Ghost Ship
When the cargo ship Bertram's Folly set sail across the ocean, it carried tons of fruit, grain, and other perishable goods with it. Experimental magic suffusing the cargo hold preserved the foodstuffs for the long voyage. Unfortunately, the ship carried stowaways in the form of a pair of rats, which gorged themselves on the food and, as a strange side-effect of the preservation magic, bred prodigiously. Within an hour, the pair became a hundred, and by the end of the trip's first day, a thousand rats devoured the entire cargo.
The first sign of trouble came when the ship's cat, Mr. Tibbles, scurried up to the crow's nest and refused to come back down. The first couple of sailors to investigate became the rat swarm's first human victims, and the remainder of the crew closed the door to the cargo hold to keep the carnivorous rats away. The door burst due to the sheer number of rats pushing on it, and the ravenous creatures made short work of all hands, leaving the ship adrift. Having no other source of food, the rats turned on each other, and the last survivor quickly died of starvation.
1. Main Deck (CR 10)
Skeletal remains of several humans and hundreds of rats litter the main deck; something has picked the bones clean. The only exception is a large, bloated rat that shows no obvious sign of its cause of death.
The rats enacted their carnage here as the crew mad their desperate but futile attempt to fight off the starving rats. When the rats triumphed, they devoured the sailors' flesh, and then they attacked each other, leaving a single survivor, which perished shortly thereafter.
Creatures: Four crewmembers returned to a mockery of life after the rats had stripped them of their flesh and continue their duties as best they can, with the purpose of finding potential seaborne victims they can consume.
Bertram's Folly Skeleton (4) CR 6
Human skeletal champion warrior 5
NE Medium undead
Init +6; Senses darkvision 60 ft.; Perception +4
AC 19, touch 14, flat-footed 16 (+3 armor, +1 deflection, +2 Dex, +1 dodge, +2 natural)
hp 78 (5d10+2d8+33)
Fort +7, Ref +6, Will +4
Speed 30 ft.
Melee mwk scimitar +11/+6 (1d6+4/18–20) or 2 claws +10 (1d4+3 plus disease)
Special Attacks disease (filth fever: Claw—injury; save Fort DC 16; onset 1d3 days; frequency 1/day; effect 1d4 Dex damage and 1d4 Con damage; cure 2 consecutive saves)
During Combat Bertram's Folly skeletons pair off against opponents and make use of their Outflank feat to overwhelm an opponent. They prefer to fight with their scimitars, but they occasionally switch to a claw attack to infect a foe with a virulent strain of filth fever.
Morale Bertram's Folly skeletons fight to the death.
Str 17, Dex 14, Con —, Int 8, Wis 10, Cha 16
Base Atk +6; CMB +9; CMD 23
Feats Dodge, Improved Initiative(B), Lightning Reflexes, Outflank, Toughness, Weapon Focus (scimitar)
Skills Climb +10, Perception +4, Profession (sailor) +7, Swim +10
Gear +1 leather armor, masterwork scimitar, ring of protection +1
2. Crow's Nest
A jingle sounds from the bucket at the top of this mast as if someone within fidgeted with a bell.
A character investigating the crow's nest finds an emaciated, but still living, Mr. Tibbles. Coaxing the animal down requires a DC 28 Handle Animal check.
Treasure: The captain placed a "lucky" charm on Mr. Tibbles's collar. This charm, a finely crafted jade dolphin, is worth 3,000 gp.
3. Belowdecks (CR 9)
The ship's virtually empty cargo hold echoes eerily with each footfall. Gnawed bags and crates are the only remains of whatever the ship carried.
The bags and crates in the cargo hold still radiate strong transmutation magic, due to the magic used to preserve the food within.
Creatures: The rat swarm's hunger was so intense that the creatures returned as ghostly versions of their former selves. They attack, appearing to pour out of the walls, when a character fully descends the ladder to the hold.
Ghost Rat Swarm CR 9
Fiendish advanced rat swarm ghost
CE Tiny undead (animal, incorporeal, swarm)
Init +8; Senses darkvision 60 ft., low-light vision, scent; Perception +18
AC 17, touch 17, flat-footed 13 (+4 Dex, +2 size, +1 deflection)
hp 53 (6d8+36)
Fort +6, Ref +9, Will +5
Defensive Abilities channel resistance +4, incorporeal, rejuvenation, swarm traits; DR 5/good; Immune undead traits; Resist cold 10, fire 10; SR 14
Speed 15 ft., climb 15 ft., fly 30 ft. (perfect), swim 15 ft.
Melee swarm (corrupting touch [9d6, Fortitude DC 18 half] plus disease) or swarm (draining touch plus disease)
Space 15 ft.; Reach 0 ft.
Special Attacks disease, distraction (DC 18), draining touch, malevolence, smite good 1/day (+6 bonus to damage rolls)
During Combat The ghost rat swarm starts combat by using its corrupting touch and malevolence attacks. If it succeeds in merging with a character, it forces that character to jump overboard, lets the character begin drowning, and the portion of the swarm involved in the malevolence returns to the main swarm. If the swarm is reduced to 20 or fewer hit points, it begins to use its draining touch, until it returns to at least 30 hit points.
Melee The ghost rat swarm fights to the death.
Str —, Dex 19, Con —, Int 2, Wis 17, Cha 20
Base Atk +4; CMB —; CMD —
Feats Improved Initiative, Skill Focus (Perception), Toughness
Skills Climb +12, Fly +24, Perception +18, Stealth +27, Swim +12; Racial Modifiers +8 Fly, +8 Perception, +8 Stealth
Disease (Su) Filth fever: Swarm—injury; save Fort DC 18; onset 1d3 days; frequency 1/day; effect 1d4 Dex damage and 1d4 Con damage; cure 2 consecutive saves. The save DC is Charisma-based.
Draining Touch (Su) A ghost rat swarm gains a touch attack that drains 1d4 Con. On each such successful attack, the swarm heals 5 points of damage to itself. When it makes a draining touch attack, it cannot use its standard ghostly touch attack.
Malevolence (Su) Once per round, a five-foot square of the ghost rat swarm can merge with a creature on the Material Plane. This ability is similar to a magic jar spell (CL 10th), except it does not require a receptacle. To use this ability, the swarm must be in the same square as a target. The target can resist the attack with a successful DC 18 Will save. A creature that successfully saves is immune to the swarm's malevolence for 24 hours. If the malevolence attack is successful, the swarm loses 10 percent of its hit points until that portion of the swarm returns.
Rejuvenation (Su) The ghost rat swarm restores itself in 2d4 days. The only way to permanently destroy the swarm is to destroy the ship it occupies.