I am the universe's punching bag.
So thought Cain as he strolled down the alley, brooding in his usual dark mood.
Suddenly, a huge troll melted out of the shadows, brandishing a huge and unsubtle-looking pistol.
"Yer money or your life."
"I-I-I-oh, shit!"
Cain ducked just as the alley wall collapsed, showering him with bricks. The impact raised bruises all over his body, but when he looked up, it seemed that the trog had suffered far worse, his face bleeding and almost smashed in from the beating he'd received. As Cain turned to run, an elephantine hand completely enveloped his head.
"Just because yer lucky doesn't mean yer don't give me yer nuyen..."
Cain felt the hairs raise on the back of his neck.
"Mummmfummf..."
He had just time to try to swear before the lightening bolt hit, burning him severely but turning the trog into Mugger Flambe. Wincing, Cain limped away...

NEW MAGICAL TRADITION: ACCIDENT PRONE
There are a few unfortunate souls whose magic is entirely beyond their control, and is as much a source of grief in their lives as it is a source of wonder in the life of a normal mage. They are the accident prone.
Accident prone can only be Aspected Sorcerors, and they suffer a number of other limitations to their powers. They cannot astrally project, preform ritual magic, or initiate with a group, and their powers cannot manifest in such a way that could not be explained away as a freak of probability. Also, they manifest largely beyond the Accident Prone's control, and often cause massive amounts of collateral damage to the surrounding area. On the bright side, their spellcasting is completely undetectable to those not astrally perceiving, and the caster adds triple their Magic attribute to the TN to determine if they are spellcasting: they also gain the metamagical technique of masking for free. This means that the vast majority of accident prone are unaware that they are Awakened, and simply assume that they are ludicrously unlucky.

Drain is manifest as collateral damage to the caster: as in the story above, the caster's hit with bricks and fried by the lightening bolt, too. The higher the Force of the spell, the more improbable the accident: a Force 2 Fireball might manifest as someone's spilled whisky igniting in the wrong place, while a Force 8 Fireball could be a meteor strike!

Can you help me flesh this out? This would be a supremely fun character to play.

Sounds like a lot of fun for Toon or something, but I think it'd ruin the feel of your average Shadowrun game pretty quick. Why would anyone want to work with someone like that?

Depends on the game. It might work in a street level or ganger game.

I think it's an interesting stepping off point, but I think it goes the wrong way. It may just be the magic manifesting itself in an untrained manner. I think this is how it should work for new characters until they actually start training to gain control over their inborn abilities. Just a thought.

That does sound like an interesting concept.
Anyone else?

i'd set it up as a paradigm, a la SOTA:64, rather than calling it a new tradition.

I don't have it. When I get my paws on it, I'll take a look at doing just that. What would be the functional/mechanical differences?

As others have said, this would work a lot better in a street level game, when you don't nessecarily HAVE to accomplish anything.

You could attempt to force the inclusion of such a sorcerer in a semi-complex setup involving two groups trying to isolate the similarities and differences between this and controlled magical exertion. Or toss in a strange cult that seems to think he's the reincarnation of Cthulu's hampster or something like that.

There are ways to get such a PC into the group for some length of time, but after the one forced inclusion (if they don't kill the oddity themselves) the other PCs should get to decide if they will ever deal with the freak again. Many groups would say "no, make a real character" a few would say "sure, what would happen to him if we didn't" and a very small selection would immediately try to scrap all their current characters and return as uncontrolled mages.

you could also have the group try to capture such a character, if possible.

although this would involve an extreme amount of Bullshitting on the GM's part, and some players wouldn't be OK with this,

paradigms, from SOTA:64, are sorta like totems for hermetics. they're much more limited, though, generally being just a one-line description of how they differ from 'standard' hermetics. i don't see anything about this concept that would require generating a whole new tradition; the differences between accident prone and hermetic sorcery are mainly just fluff. you could play this character type without making any rules changes at all, just change how you describe his spells going off, and how he takes drain.

yeah, they're not totems, but that's the closest relatable concept for someone who hasn't read SOTA:64.

Heh, funny idea. I think its a bit better used as an NPC, but whatever floats your boat. The only way this type of character could work out in a group would be if the whole group followed this Accident Prone tradition. Oi Vey! Talk about a nutty sesh.