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Giant Rat

Small Beast · · CR 1/8

  • Beast
  • Small
  • Tier 1

As a small beast (unaligned), Giant Rat carries CR 1/8. Common in forest, swamp, underground, and urban environments. Sourced from Monster Manual (5e 2014) and Monster Manual (5.5e 2024).

Stat Block

Challenge Rating
1/8
Type
Beast
Size
Small
Alignment
Speed
Habitats
Forest, Swamp, Underground, Urban
Sources
Monster Manual (5e 2014), Monster Manual (5.5e 2024)

Ecology

Giant rats infest urban sewers, abandoned ruins, dungeons, and grain silos in numbers that strain belief. They breed prolifically: a single mating pair can produce sixty descendants in a year. They eat anything organic, from refuse to corpses to live infants if undefended. They carry diseases, parasites, and worse, occasionally serving as hosts for supernatural plagues. They tunnel through soft stone and old mortar.

Behaviour

Giant rats are pack scavengers with limited individual courage but considerable collective aggression. They flee solo encounters but swarm when numbers exceed half a dozen. They are intelligent enough to recognize trapped paths and avoid them after one casualty. Wererats can command them, and rat-kings (six rats fused at the tail) lead larger swarms. They are nocturnal and despise bright light.

Origin

Most giant rats are mundane vermin grown large from steady access to magical waste, sewer effluent, or alchemical runoff. A minority are deliberately bred by wererats for use as mounts and steeds in their underground societies. Lore tells of an ancient first rat called the Plague-Mother, whose litter populated the world's first city sewers, and every rat-king is said to be possessed by a fragment of her appetite.

All BeastsForestSwampUndergroundUrban

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Frequently Asked Questions about Giant Rat

What is the challenge rating of Giant Rat?
Giant Rat has a challenge rating of 1/8. It works against low-level groups.
What type of creature is Giant Rat?
By creature type, Giant Rat is a beast, small size.
Where does Giant Rat live?
Giant Rat is typically encountered in Forest, Swamp, Underground, Urban.
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