The Taser X-12 shotgun, “optimized” to fire the less-lethal Taser 12 gauge projectile. The neat thing about the X12 (which is a Mossberg design) is that it’s not compatible with lethal 12 gauge rounds. Depending on to whom you’re speaking, this is either a good thing or a bad thing; for a police department from a liability standpoint it’s a good thing, since no one will be accidentally slipping a round of 00 buck into their “less-lethal” shotgun.
I don’t know yet whether or not the X12 will be available to non-LE types like you and I, and for some reason I highly doubt that it will be. That’s actually too bad if you ask me, because I would recommend this to people who might be uncomfortable deploying lethal force against another human for whatever reason.
When I look at stuff like the X12, the sci-fi nerd in me kicks up just a little bit and says “soon…we’ll be able to set for stun…soon”, which of course I think is just fantastic.