Dire Rat
This filthy rat is the size of a small dog. It has a coat of coarse fur, a long and scabby tail, and two glittering eyes.
Dire rats grow up to 2 feet long and weigh up to 25 pounds. They are common menaces in dungeons and city sewers alike.
Source(s) 3.5E Monster Manual I, 3E Monster Manual I, 3E Player’s Handbook, Urban Arcana

Dire Rat | |
Small animal | |
Hit Dice | 1d8+1 (5 hp) |
Initiative | +3 |
Speed | 40 ft. (8 squares), Climb 20 ft. |
Armor Class | 15 (+1 size, +3 Dexterity, +1 natural), touch 14, flat footed 12 |
Base Attack/Grapple | +0/-4 |
Attack | Bite +4 melee (1d4 plus disease) |
Full Attack | Bite +4 melee (1d4 plus disease) |
Space/Reach | 5 ft./5 ft. |
Special Attacks | Disease |
Special Qualities | Low-Light Vision, Scent |
Saves | Fort +3, Ref +5, Will +3 |
Abilities | Strength 10, Dexterity 17, Constitution 12, Intelligence 1, Wisdom 12, Charisma 4 |
Skills | Climb +11, Hide +8, Listen +4, Move Silently +4, Spot +4, Swim +11 |
Feats | Alertness, Weapon FinesseB |
Environment | Any |
Organization | Solitary or pack (11-20) |
Challenge Rating | 1/3 |
Treasure | None |
Alignment | Always neutral |
Advancement | 2-3 HD (Small); 4-6 HD (Medium) |
Level Adjustment | – |
Combat
Dire rat packs attack fearlessly, biting and chewing with their sharp incisors.
Disease (Ex) : Filth fever-bite, Fortitude DC 11, incubation period 1d3 days, damage 1d3 Dexterity and 1d3 Constitution. The save DC is Constitution-based.
Skills: Dire rats have a +8 racial bonus on Swim checks. Dire rats have a +8 racial bonus on Climb checks and can always choose to take 10 on Climb checks, even if rushed or threatened.
Dire rats use their Dexterity modifier for Climb and Swim checks.