I typed this command in a cmdBlock :
/summon Witch ~ ~1 ~ {AttributeModifiers:[{Name:generic.movementSpeed,Base:0.0}]}
I don't think it's wrong, so I don't know why the Witch still moves instead of being still...
About this one, I'm less sure it has the right syntax :
/give @p 276 1 0 {AttributeModifiers:[{Name:generic.attackDamage,Base:8.0}]}
But same happens, Attributes seems to be not working...
Comments


Can't use attributes on mobs in 14w08a

use: http://minecraft.gamepedia.com/Chunk_format#Entity_Format too see all the names of the data, when looked closely, I think you'll see you're problem

I already had, and I also looked at multiple vidoes explaining how to do this.
Use this command yourself:
/summon Witch ~ ~1 ~ {AttributeModifiers:[{Name:generic.movementSpeed,Base:0.0}]}

@unknown is right, it works perfectly fine when using
/summon Witch ~ ~1 ~ {Attributes:[{Name:generic.movementSpeed,Base:0.0}]}

Have you tried looking at the spawned mob for more than 2 seconds? No, it doesn't work

After relogging twice it fixed the problem. I'm not sure why...

Tested for 1.8.2-pre1. Still in it, when you are regenerating your health and you stop using, you will need to take damage again at least to reduce your health back to the normal 20.
it's Attributes, not AttributesModifiers