Game Text:

Rebreather Object on Utility Belt:

Give this character a power action if it occupies water terrain. When you do, until the end of the turn, the character possesses "Transporter Dolphin symbol" and can use the Move and Attack ability as a free action but does not modify its attack value by -2 when using it.

Move and Attack:

This character can use Hypersonic Speed if it is not adjacent to an opposing character when given the power action, but its attack value is modified by -2.

Question:

Does the swimming transporter modify its attack while using the Rebreather?

No, you do not the -2 to attack

I thought you don't get any bonuses from another power if you can already use it? Isn't this why a character with Smoke Cloud showing can't use the Smoke Pellets from the Utility Belt? Same effect as smoke cloud- with a bonus.

Wait, what is he asking?

Isn't the OP simply asking if the swimming transporter symbol given by the rebreather ignores the -2 penalty of move and attack?

He is asking if the rebreather on a swimming transporter benefits from the negation of the -2 since it cannot gain move and attack via the rebreather since it has it already. I would say yes because you would not gain move and attack from the rebreather since you have it already, but the rest reads "but do not modify its attack value by -2 when using it". "It" is move and attack so this effect should trigger regardless of what move and attack is used, whether it is from the rebreather or dial.

I believe this is different than the resource gas pellets because that power is a special smoke cloud. This is a modifier to move and attak, not a special move and attack. I think it is more similar to the relic gas pellets where you can move after using smoke cloud regardless of if you use it from the relic or not. If it had said "When using this move and attack" or something to that effect I'd say it is all bundled together but as is the second bit seems like it would affect any move and attack.

Then again, that's my take and I could be totally wrong and it could be considered a "special move and attack".

Wow, I thoroughly misunderstood the question. That wasn't even in my top 3 guesses.

Don't think you get the benefit from the rebreather either, it's the similar issue to the smoke cloud/smoke pellet thing krusticlese pointed out.

No. Because of all the same stuff with the smoke cloud/gas pellet stuff and duplicated game effects.

Basically, you have to use the power action to activate the effects of the re-breather. The "does not modify it's attack by -2" is part of using the effects of the rebreather.

Did your regular swimming transporter use a power action to activate the re-breather? No because it can't use the special move and attack because it already has the swimming transporter/move and attack ability. So since you can't ever use swimming transporter from the re-breather due to being unable to duplicate game effects, you can't ever use the "does not modify it's attack by -2" portion of the re-breather.

He would not get the bonus. You are giving him a power action to gain the symbol. Since the character already has that symbol, nothing happens and you can't use this rest of the text because it is contingent on receiving from this power. If it were separated out a little bit more it could work. If it said some thing like give this character a power action to gain for the rest of the turn. It may then use the move and attack ability as a free action. When this character uses move and attack it does not apply the -2 modifier to its attack.
As stated though, it would not work.

Yeah, I agree with those who said you don't get the benefit and still modify your attack by -2.

This is because the part saying not to modify your attack value is contingent on the power action being taken ("When you do..."). If instead there was a separate clause that just said something to the effect, "When this character uses the move and attack ability, don't modify its attack value by -2", then I think it would apply to those who have the transporter symbol alreadu, since it's not dependent on using the move and attack granted by the Rebreather.

If you can't the do bold part in the first place, everything written after it is blank. So don't put the Rebreather on someone who already has .

Or just run an army of Manphibians and slap the UB with the rebreather on another SHIELD figure- pick the Helboy Temple map and go nuts!

Is there a reason a figure with couldn't take a power action while it occupies water terrain to activate the re-breather? Whether or not the re-breather would have any effect is another matter, but it seems to me that you could still use up the re-breather with a power action, if you really wanted to.

Refer to Wilx's post above, he explained it rather well.

^ Ninja, ninja!