mohrg
http://www.d20pfsrd.com/bestiary/monster-listings/undead/mohrg
any one have any idea what the effect type of mohrg paralysis is? (poison, mental, fear, enchantment etc etc)
and what is the save to avoid it. (fort, will, reflex?)
and now that I am on it what is the save based on, charisma? str?
Paralysis does not possess a sub-type. Only resistance/immunity to paralysis specifically would apply.
The save against paralysis is Fortitude.
The DC is based on the mohrg's Charisma modifier. Normally paralysis DCs are set by a creature's Constitution modifier. However, undead creatures use Charisma in place of Constitution for things such as this.
If an ability is not described in a monster's text, it is typically because it is a universal monster rule. Those are covered in the back of the Bestiary, or here.
Since the general rule for saves is 10 + 1/2 HD + ability mod, you can reverse engineer the save for the paralysis to be charisma based. 10 + 1/2 HD (7) + ability focus (2) + ability mod (X) = 21. Some basic algebra later, and X equal 2, which is the bonus for a Cha of 14.
Looking in the Universal Monster Rules for paralysis, you see the following.
Paralysis (Ex or Su) This special attack renders the victim immobile. Paralyzed creatures cannot move, speak, or take any physical actions. The creature is rooted to the spot, frozen and helpless. Paralysis works on the body, and a character can usually resist it with a Fortitude saving throw (DC 10 + 1/2 paralyzing creature's racial HD + paralyzing creature's Con modifier; the DC is given in the creature's description). Unlike hold person and similar effects, a paralysis effect does not allow a new save each round. A winged creature flying in the air at the time that it is paralyzed cannot flap its wings and falls. A swimmer can't swim and may drown. The duration of the paralysis varies and is included in the creature's description.
Format: paralysis (1d4 rounds, DC 18); Location: Special Attacks and individual attacks.
We've already determined that the save is Cha based, which makes sense since most Con based abilities become Cha based for undead. You also find out that it's usually a fortitude save. Since nothing in the entry indicates that it's not, it's a Fort save. Additionally, like ghouls, a mohrg's paralysis doesn't seem to have a type; it just works because undead. So bonuses against poisons or enchantments or whatever don't go into that save.
Hope that helps.