Apologies if this doesn't format well on the forum.
This little bugger will be in Castles & Crusades Oriental Adventures.
The word "Obaki" I just made up because it sounds vaguely Japanese to me. (I hope it's not a real word, or worse yet, something obscene. can you imagine?)
OBAKI (Rat-Spider Goblin)
NO. APPEARING: 1 – 4
SIZE: small in all forms
MOVE: 30 walk all forms, rat also swim 15, spider also climb 30
AC: 13 humanoid or rat, 16 spider
ATTACKS: by weapon humanoid / bite 1d4 rat/ bite 1d6 & sting 1d4 + poison spider
SPECIAL: Twilight vision & darkvision (all shapes), poison & web (spider), may have magic items (humanoid)
An obaki (oh BAH kee) is an intelligent mischief maker who may cause all sorts of trouble just for the joy of spreading misfortune and evil, and they enjoy harming and killing those weaker than themselves or those frightened of rats and spiders. They can eat any creature, vegetable, or carrion, but prefer the flesh of humans, hengeyokai (shifters), river folk and korobokuru (dwarves). Obabi will band together with Oni or other evil beings to spread disharmony wherever they can.
An Obaki is an evil shape shifter that can take three different forms, instantly changing shape at will. One is a monstrous spider, the body about three feet in size, with a hard black hairy shell. Another is that of a huge rat 2 – 3 feet in length, and the third is that of a small ugly humanoid between 3 – 4 feet in height. In any of their forms, the obaki has beady little red eyes and sharp yellow fangs.
In their humanoid form, they resemble ugly, malevolent children with floppy ears and fangs. They have spindly limbs, chalky-colored, flaky skin and coarse black hair. This is their only shape with hands, and the only one in which they can use magic items or wear armor, improving the AC listed above. Any items they have on their person in humanoid form will transform with them when they shape shift, becoming inaccessible and inert, but reappearing when they return to humanoid form. The Spider form has a rock hard carapace and allows the creature good climbing ability, a venomous sting, and web spinning ability. In the creature’s rat form, the rat is 2 – 3 feet in length with very dark brown or black oily-looking fur. It can swim and climb and squeeze through tiny openings as small as six inches in diameter.
Combat: Obaki can change shape at will and will do so to their advantage. They may assume rat form to hide or take spider shape and gain surprise by lowering themselves from webs to strike from above.
Web: In spider form the Obaki often waits in their webs or in trees, then lowers itself silently on silk strands to leap onto prey passing beneath. A single strand is strong enough to support the spider and one creature four times as large. An Obaki can also throw a web eight times per day. They may create sheets of sticky webbing of 20 to 30 feet square. They usually position these sheets to snare flying creatures but can also try to trap prey on the ground. They can move across their own web at their climb speed and can pinpoint the location of any creature touching its web.
Poison: A victim bitten by an Obaki in spider form suffers 1d6+3 damage from the venom unless they make a constitution save. A successful save halves this damage and negates any affects in the following rounds. If the victim fails the first save, they take 1d4+2 damage the following round (save again for half). Further, if they fail this second save they become paralyzed for 2d6 rounds. There are no further affects after the second round.