This power has crazy potential especially considering the following combo.

Tear Gas + Stunning Blow + Flasbang

If this works the way I think it should Robin can move half his speed, throw down a smoke cloud and then use the free incap to activate stunning blow.

Perplex makes him even sweeter so he can boost his attack or defense in case of retaliation. This gives him an 11 attack or 19 defense.

Now I just have to get one

Flashbang doesn't work like that anymore. It's now a full-speed, one-time use Flashbang.

The interesting thing about Tear Gas Grenade is that I believe it allows Robin to make a ranged attack against a character who benefits from Steal in clear terrain with the Deep Shadows BFC in play.

Here's the scenario: Deep Shadows is in play. Clear terrain is now considered hindering terrain for the purposes of drawing line of fire. Smoke Cloud tokens can only be placed in clear terrain.

On a wide open area of the map, Robin is four squares away from an opposing Question. Robin can't make a ranged attack against an opposing Question (who is benefitting from Stealth due to Deep Shadows) but he can place a Smoke Cloud token in her square (as it is still clear terrain for that purpose).
Then Robin can use Incapacitate as a ranged attack against Question, ignoring the effects of hindering terrain as described in his special power.

In normal constructed games this may not come up much, but in sealed Arkham Asylum I suspect that it will - because there's so much Stealth in the set, and Deep Shadows is one of the BFCs.

The underlined portion is not correct. You are thinking of Barrier. This is Smoke Cloud from the PAC, note the underlined portion:

So to be clear, Robin can go around tear-gassing incapping characters in stealth?

so the old Flashbang, even if the cost is different is no longer valid?

I figured they could be considered two diff feats since the price/effect was different.

Why don't you add Maneuver onto that mess and really do some crazy stuff?
Robin runs his full movement, drops a flashbang 6 squares away on a Stealth figure, incaps that figure with a close combat attack, does the damage with Stunning Blow then maneuvers the character out of hindering terrain; adjacent to Robin at the end of it all for Batman to tag the poor soul with a Ranged Combat Attack.

That is vicious.

How do you incap a figure 6 squares away witha close combat attack?

Robin has a range of 6 so he can put his smoke cloud 6 squares away then use Incap on the stealth figure that the smoke token is put under.

Incap can be a close combat or a ranged combat action. Use it as a Close Combat action and that will trigger Maneuver.

Is he allowed to use Stunning Blow? He doesn't actually have Incap, your just allowed to use it with smoke cloud...But I guess it's like saying a special power let's you use powers...

It doesn't say Robin gets to use Incapacitate as if he were adjacent to the target or as if he occupies any square other than the square he actually occupies. If you are 6 squares from the target you just dropped a smoke cloud under, you would making a ranged combat Incapacitate attack against him, not close combat. So I think Maneuver would only be applicable if you are adjacent to the target you're using the free Incap on, and thus making a close-combat attack.

The SP facilitates this by allowing Robin to ignore hindering terrain for the Incapacitate. Robin needs only the ability to draw line of fire to the square to drop the smoke cloud, then he automatically gets to ignore that smoke cloud, and any hindering terrain under it, to make a ranged Incapacitate attack (or close if Robin happens to be Adjacent).

I would also extend this to mean that if Robin is based by an opposing character, he would not be able to use the SP to make a ranged Incapacitate attack against another.

Stunning Blow is also questionable, though I would guess it's applicable. The question is: if a SP grants you a power if X and if Y and if Z, does that mean you can say you possess it for purposes of feat pre-requisites? This may have been the gray-area they wanted to avoid back when SP's didn't fulfill pre-requisites in the first place.

My 2 cents, anyway.

So wait can you use the text on the old Flashbang in an unrestricted game if you prefer it to the new one?

You can only make a close combat ation against a figure to which you are adjacent to. At the same time you cannot make a ranged combat action against a figure that you are adjacent to (barring a sharpshooter). Converselly you can make a ranged combat action against a figure that you are not adjacent to (barring line of fire issues), but you cannot make a close combat action against this figure (barring giants)

What the incap power is saying is that if you are adjacent to an opposing figure, then you can still use incapacitate as a close combat action. If you are not adjacent to the figure you can still use incapacitate as a ranged combat action. You have the option to use it either way, but are still governed by the overall rules of close combat and ranged combat.

There is only one way that your combo will work. when you move before doing the smoke cloud, you need to move right up to be adjacent to the target. Smoke cloud is not a combat action (not consdered ranged or close) so you can drop it right on the target. Then you can do the incapacitat as a close combat action, and inturn the stunning blow and maneuver

Actually, the range factor is irrelevant in the Flashbang & Maneuver tactic. Maneuver is a close combat tactic. Flashbang allows you to use SC either before or after moving. To use it with Maneuver, you would presumably use it after moving adjacent to your target, thus enabling you to make a close combat incap attack, and thus activating Maneuver.

Flashbang was made for AA Robin. It's an incredible first strike tactic as Robin can use his L/C with it and come bounding over blocking/elevated terrain for his full movement and perform an Incap attack. Add other feats like Maneuver and Stunning Blow to suit your taste.

Ahh...I see what you are saying and it does sound correct. However it is a little strange that the Tear Gas SP says attack and not target.

Had it said Target, I would agree with you 100% but since it says attack, I would like further clarification...though I believe your ruling is correct.