for something like that you would need to change the attributes of the mob the easiest way to do so would be executing a command like this on mob tick update once or any other event but when mob spawns (this doesn't worrk for some reason)
/entitydata @e[type= your mob here,c=1] {Attributes:[{Name:"generic.knockbackResistance", Base:1}]}
I don't 100% get what your saying but i have a way to do that, when the is hit it will get hit with slowness 100 for how ever long
Doesn't have any effect :/
for something like that you would need to change the attributes of the mob the easiest way to do so would be executing a command like this on mob tick update once or any other event but when mob spawns (this doesn't worrk for some reason)
/entitydata @e[type= your mob here,c=1] {Attributes:[{Name:"generic.knockbackResistance", Base:1}]}