@Override
	public boolean invoke(MOB mob, Vector commands, Physical givenTarget, boolean auto, int asLevel)
	{
		Physical target=mob;
		if((auto)&&(givenTarget!=null)) target=givenTarget;
		boolean oldOne=false;
		for(final Enumeration<Ability> a=target.effects();a.hasMoreElements();)
		{
			final Ability A=a.nextElement();
			if(A instanceof Spell_ManaShield)
				oldOne=true;
		}
		if(oldOne)
		{
			mob.tell(mob,target,null,_("<T-NAME> <T-IS-ARE> already affected by @x1.",name()));
			return false;
		}

		if(!super.invoke(mob,commands,givenTarget,auto,asLevel))
			return false;

		final boolean success=proficiencyCheck(mob,0,auto);

		if(success)
		{
			// it worked, so build a copy of this ability,
			// and add it to the affects list of the
			// affected MOB.  Then tell everyone else
			// what happened.
			final CMMsg msg=CMClass.getMsg(mob,target,this,verbalCastCode(mob,target,auto),auto?"":_("^S<S-NAME> invoke(s)@x1 protective shield.^?",adjective()));
			if(mob.location().okMessage(mob,msg))
			{
				mob.location().send(mob,msg);
				mob.location().show(mob,target,CMMsg.MSG_OK_VISUAL,_("@x1 protective aura of mana surrounds <T-NAME>.",CMStrings.capitalizeAndLower(adjective()).trim()));
				beneficialAffect(mob,target,asLevel,0);
			}
		}
		else
			return beneficialWordsFizzle(mob,target,_("<S-NAME> attempt(s) to invoke@x1 protective shield, but mess(es) up.",adjective()));


		// return whether it worked
		return success;
	}