Tarrasque wanna be
swan this is what you dreaed i would post
Mbwun
Medium size abberation
H.D. 6D8:48
Iniative:+4
Speed:50 feet/30 on two feet
A.C.:19=10+0+0+4+5/Touch:14/flat foot:15
Base attack/grapple:+6/+6
Attack:claw(1D8+3),tail(1D6+1),bite(1D6+2)
Full attack:2claws(1D8+3),1tail(1D6+1),Bite(1D6+2)
Space/reach:5/5
speacial attacks:Mbwun infection,decapitate
Speacial qualities: regenaration10,darkvision(60 feet),dmg.reduction10/magic,immunity:cold electric poison
Saves:fort+10,ref.+15,will+8
Abilities:str19,dex19,con12,int12,wis13,cha9
Feats:claeve,Grt.strength,blind fight,combat reflexes
Skills:listen+3,Search+4,survival+5
enviroment:warm forests,swampsand underground
Organization:solitary,pair,pack
treasure:standard(lots of shiny obgects)
Alignment:any evil
C.R.:not quite sure on this one
Advancment:7-10(large)
This appaers to be a haevily muscled bipedal reptile with bony plates covering vital areas and patches of fur and scales elsewhere it's most prominent and tell tale feature is a sadisticly large middle claw on the front pair of claws. the mbwun prefers to ambush prey at night because of their light sensitive eyes and can driven off for few minutes with a bright light. they can be highly sadistic torturing prey slowly
Speaical attacks: Mbwun Infection:3/day only used with a successful bite
if target does not recieve a remove disease spell in 1D4 days he becomes a mbwun
decapitate:6/day if tarcet gets hit with a crit. claw attack they can be killed instantly
Excellent, some actual stat data.
The only problem that really jumps out at me is the lack of saving throws for the abilities. The spawn ability should have a Fortitude DC to fight off the infection, especially since unlike other spawning monsters this one doesn't have to wait until the target dies. The other ability (death on critical) would be better served by simply making the crit multiplier for that ability obscene, or else explicitly giving it a "vorpal" strike.
You did all right though, good job.