There is one rather bizarre idea I have had for a feat for many years (one that could be considered a joke, actually), and I am wondering whether it would work in either NWN game. (I believe it would not work in the tabletop game, incidentally.)

By work, I mean that the following should hold true:
1. that it be possible to implement the feat, and
2. that it actually be possible to get some use out of said feat. (In this case, that it be possible to damage an enemy with this feat.)

Anyway, here is the feat in question:

Instantaneous Blast:

Benefit: When this feat is taken, a burst of energy is released in all directions, doing 2d6 damage per level of the character taking the feat to every hostile creature within 60 feet.

Special: This feat may be taken multiple times. Each time the feat is taken, another burst of energy is released.

Why not?

The other question is, can the feat be taken at a time that it would be useful (for example, could you level up and take the feat in the middle of a battle)?

(Of note, this isn't the only silly D&D 3.x feat I have thought of. Another feat, which I created to illustrate what I see as strange game design, allows the character to choose any extraordinary ability that she possesses and get rid of it; turns out that this could make the Wilder overpowered (because Psychic Enervation is listed as s separate ability, when it really should be part of Wild Surge). Another idea I had was a spell that would suppress extraordinary abilities, leading to strange cases like merfolk losing the ability to breathe air.)

Well, yes, it could be taken when useful, because you CAN level-up in the middle of a battle.

I have heard of Clerics that stay under-leveled for the whole game, and when they are in the middle of a zone, they activate a miscellaneous item that converts them and all of their unrealized potential into kinetic energy. It's actually everyone's worst nightmare in MidEast PVP servers. Colossal damage radius and much rage ensues, but the DM has yet to intervene.