“We called him Rat Slayer Eric, but that was before he went nuts and killed all those folks and we had to put him down. Some folks swore they saw a rat spirit reveling in his death nearby when the guard cut him down.”
Rat ghosts come to be when a particularly special giant rat is killed. They’re one in a thousand rats that become giant rats, but with the quantities of giant rats being killed by adventurers every day, you shouldn’t be surprised to meet one or more of these.
Small undead, chaotic evil
Armor Class: 12
Hit Points: 9 (2d8)
Speed: 0 ft., fly 40 ft. (hover)
|7 (-2)||15 (+2)||10 (+0)||4 (-3)||11 (+0)||10 (+0)|
Damage Resistances: acid, fire, lightning, thunder; bludgeoning, piercing, and slashing from nonmagical attacks.
Damage Immunities: cold, necrotic, poison
Condition Immunities: charmed, exhuastion, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained
Senses: darkvision 60 ft., passive Perception 10
Challenge: 1 (200 XP)
Ethereal Sight. The rat ghost can see 60 feet into the Ethereal Plane when it is on the Material Plane, and vice versa.
Incorporeal Movement. The rat ghost can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.
Withering Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 7 (2d4+2) necrotic damage.
Etherealness. The rat ghost enters the Ethereal Plane from the Material Plane, or vice versa. It is visible on the Material Plane while it is in the Border Ethereal, and vice versa, yet it can’t affect or be affected by anything on the other plane.
Possession (Recharge 6). One humanoid the rat ghost can see within 5 feet of it must succeed on a DC 10 Charisma saving throw or be possessed by the rat ghost; the rat ghost then disappears, and the target is incapacitated and loses control of its body. The rat ghost now controls the body but doesn’t deprive the target of awareness. The rat ghost can’t be targeted by any attack, spell or other effect, except ones that turn undead, and it retains its alignment, Intelligence, Wisdom, Charisma, and immunity to being charmed and frightened. It otherwise uses the possessed target’s statistics, but doesn’t gain access to the target’s knowledge, class features, or proficiencies.
The possession lasts until the body drops to 0 hit points, the ghost ends it as a bonus action, or the ghost is turned or forced out by an effect like the dispel evil and good spell. When the possession ends, the rat ghost reappears in an unoccupied space within 5 feet of the body. The target is immune to this ghost’s Possession for 24 hours after succeeding on the saving throw or after the possession ends.
No one thinks twice about killing off giant rats, until their ghosts come back for revenge, bringing possession to low level encounters with them.