@Override
	public boolean invoke(MOB mob, List<String> commands, Physical givenTarget, boolean auto, int asLevel)
	{
		if((!mob.isInCombat())||(mob.rangeToTarget()<1))
		{
			mob.tell(L("You really should be in ranged combat to cast this."));
			return false;
		}
		for(int i=0;i<mob.location().numItems();i++)
		{
			final Item I=mob.location().getItem(i);
			if((I!=null)&&(I.fetchEffect(ID())!=null))
			{
				mob.tell(L("There is already a wall of air here."));
				return false;
			}
		}

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

		final Physical target = mob.location();


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

		if(success)
		{

			final CMMsg msg = CMClass.getMsg(mob, target, this,verbalCastCode(mob,target,auto),auto?L("An swirling wall of air appears!"):L("^S<S-NAME> conjur(s) up a swirling wall of air!^?"));
			if(mob.location().okMessage(mob,msg))
			{
				mob.location().send(mob,msg);
				final Item I=CMClass.getItem("GenItem");
				I.setName(L("a wall of air"));
				I.setDisplayText("");
				I.setDescription(L("The air is swirling dangerously."));
				I.setMaterial(RawMaterial.RESOURCE_NOTHING);
				CMLib.flags().setGettable(I,false);
				I.recoverPhyStats();
				mob.location().addItem(I);
				theWall=I;
				beneficialAffect(mob,I,asLevel,10);
			}
		}
		else
			return beneficialWordsFizzle(mob,null,L("<S-NAME> incant(s), but the magic fizzles."));

		// return whether it worked
		return success;
	}