Wester

Went to start the bike this morning and after running for about two seconds it cut out.

There was then nothing on the starter at all and the meta alarm was not responding. Horn was working as were lights and then after leaving it standing for about thirty seconds there was an audible hiss and then a ton of white smoke from under the rear seat.
I'm guessing reg/rec is just completely fried but am at a loss to explain how or why it happened, Bike was running fine last night.

I'm looking for idea's on what to do next and wether I can expect a knacked battery too.

Cheers!