Hey Pathfinders, can you provide some feedback on this? I found a cool pack of rats at the dollar store, and it inspired me to make this Necrotic Rat. Its an Advanced (3) Dire Rat with 5 additional hit dice, and some cool necromantic powers. What's unique is that it is fleshy and not undead. The story could involve it having been bred by necromancers in some homebrew world of your choosing. Have a look, let me know what you think? Negative feedback is welcome if you find any mistakes. Thanks!!!
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Necrotic Dire Rat [+5 HD (Adv +3) CR7]
XP: 3,200
N Large animal
Init +7; Senses low-light vision, scent; Perception +20
DEFENSE
AC 24, touch 16, flat-footed 17 (+7 Dex, -1 size, +8 natural)
HP 86 (6d8+60)
Fort +15, Ref +12, Will +9
OFFENSE
Speed 40 ft., climb 20 ft., swim 20 ft.
Melee bite +15 (1d8+12 plus disease), 2 claws +11 (1d6 plus energy drain), rend (1d8+12)
Space 10 ft., Reach 10 ft.
Special Attacks disease, energy drain/false life, rend
STATISTICS
Str 35, Dex 25, Con 31, Int 14, Wis 25, Cha 16
Base Atk +4; CMB +17; CMD 34 (38 vs. trip)
Feats Skill Focus (Perception), Multi-attack
Skills Climb +23, Perception +20, Stealth +16, Swim +23, Acrobatics +11, Fly +11
Racial Modifiers uses Dex to modify Climb and Swim
ECOLOGY
Environment any urban, wilderness, or underground setting
Organization solitary, pair, or triad
Treasure none
SPECIAL ABILITIES
Disease (Ex) Necrotic fever: Bite-injury; save Fort DC 17; onset instantaneous; frequency 1 round; effect 1d2 Con damage; cure 2 consecutive saves. Once a creature saves versus The save DC is Constitution-based.

This malevolent rat is the size of a horse. It has a coat of coarse fur, a long and scabby tail, and two glittering eyes.

Necrotic rats can grow up to 10 feet long and weigh up to 180 pounds. They are often grown by necromancers as companions and dwell in desolate castles, dungeons and city sewers alike, and tend to stay in the area their master once dwelt, long after its necromantic master was destroyed.

EnergyDrain/FalseLife (Su) A creature hit by a Necrotic Rat (or other natural weapon) gains one negative level. Only 1 negative level may be bestowed per round. When this supernatural ability draws energy from its victim, the necrotic rat receives +5 temporary hit points. This ability only functions once per round regardless of the number of attacks it makes.

I would change it to magical beast.

Might change the wording of Energy drain/falselife from A creature hit by a Necrotic Rat (or other natural weapon) gains one negative level.

to

Once per round as a free action the necrotic rat can imbue one of its natural attacks to bestow 1 negative level. This heals the rat of 5 hp of damage, excess damage is bestowed as temporary Hit points which fade after one hour.

a little less confusing in my opinion.

Once per round as a free action the necrotic rat can imbue one of its natural attacks to bestow 1 negative level. This heals the rat of 5 hp of damage, excess damage is bestowed as temporary Hit points which fade after one hour.

Instead of this, you could simply have the Energy Drain happen with one specific attack, most like the bite, or maybe the rend. It would happen less often with the rend, but I believe a few other monsters do it that way, and it would still remain consistent and deadly.

I like the idea of this creature. I like normal-sized rats, but this one would creep me right out.

I integrated the thoughts above into the information below. I used ciff rice's suggested text for clarity, and kept a few words of flavor text at the end to continue to creepy factor. I prefer to keep the negative level attacks more frequent than DemonicEgo suggested i.e. once per round. This makes the rates quite fearsome, even at higher levels of play where there may be 3 rats for an encounter level of 10. What do folks think about the stats for Necrotic Fever? Keep the feedback coming. Thanks!
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Necrotic Dire Rat [+5 HD (Adv +3) CR7]
XP: 3,200
N Large magical beast
Init +7; Senses low-light vision, scent; Perception +20
DEFENSE
AC 24, touch 16, flat-footed 17 (+7 Dex, -1 size, +8 natural)
HP 86 (6d8+60)
Fort +15, Ref +12, Will +9
OFFENSE
Speed 40 ft., climb 20 ft., swim 20 ft.
Melee bite +15 (1d8+12 plus disease), 2 claws +11 (1d6 plus energy drain), rend (1d8+12)
Space 10 ft., Reach 10 ft.
Special Attacks disease, energy drain/false life, rend
STATISTICS
Str 35, Dex 25, Con 31, Int 14, Wis 25, Cha 16
Base Atk +4; CMB +17; CMD 34 (38 vs. trip)
Feats Skill Focus (Perception), Multi-attack
Skills Climb +23, Perception +20, Stealth +16, Swim +23, Acrobatics +11, Fly +11
Racial Modifiers uses Dex to modify Climb and Swim
ECOLOGY
Environment any urban, wilderness, or underground setting
Organization solitary, pair, or triad
Treasure none
SPECIAL ABILITIES
Disease (Ex) Necrotic fever: Bite-injury; save Fort DC 17; onset instantaneous; frequency 1 round; effect 1d2 Con damage; cure 2 consecutive saves. Once a creature saves versus The save DC is Constitution-based.

This malevolent rat is the size of a horse. It has a coat of coarse fur, a long and scabby tail, and two glittering eyes.

Necrotic rats can grow up to 10 feet long and weigh up to 180 pounds. They are often grown by necromancers as companions and dwell in desolate castles, dungeons and city sewers alike, and tend to stay in the area their master once dwelt, long after its necromantic master was destroyed.

EnergyDrain/FalseLife (Su) Once per round as a free action the necrotic rat can imbue one of its natural attacks to bestow 1 negative level, as it draws the vicim's energy to itself. This heals the rat of 5 hp of damage, excess damage is bestowed as temporary hit points which face after one hour.

Disease (Ex) Necrotic fever: Bite-injury; save Fort DC 17; onset instantaneous; frequency 1 round; effect 1d2 Con damage; cure 2 consecutive saves. Once a creature saves versus The save DC is Constitution-based.

What happens once a creature saves?

Claws are typically primary attacks. Is it intended that these are secondary, and that they give no strength to damage?

Also, I noticed he has Multiattack, but it doesn't do anything. He could also use another feat. I recommend Endurance and Diehard.