I'm new to GMing Shadowrun and I have a few questions for you fine folks. One of my players, a Shadowrun veteran, has a shaman with (amongst other things) the Mind Probe spell. I have two questions on how it works - does the target get a spell resistance test (yes, right?) and, more importantly, since the spell is sustained, does that mean that he would enjoy however many successes he had as long as the target was in range, or would each additional piece of info force a reroll at the +2 cumulative penalty?

From memory; the spell requires a willing participant. If the participant isn't willing, he or she gets a Willpower(Force) test to resist. Stage successes up and down as appropriate.

From the way you asked Im going to assume two things:
1) The target is unwilling
2) The caster is sustaining the spell

Assuming those are correct, then yes the target gets a normal resistance test using willpower against the spells force. As long as the caster has any net successes he may probe for 1 piece of information per initiative pass.

As long as the spell is sustained, and the target is a valid target (in range, didnt go through a ward, etc) then the caster may continue to probe without penalty. Only if the spell is dropped (voluntarily by the caster or otherwise) and then recast on the same target before the "targets willpower hours" window has passed does the +2 penalty come into play. It will only really apply if the caster fails to affect a target and so casts again, or if the caster needs deeper information and so drops the spell and casts again hoping for more successes.

Hope that helps.

I would if the spell had a threshold. Far as I know it doesnt.

Although a Threshold is definitely an interesting idea for the spell, Thresholds are only for Manip spells (such as Control Thoughts) but not Detection spells.

Sphynx

Echo that. It's a pretty powerful spell, especially if cast above, say, force 4 or so.

If you want to be a complete rotter (and what GM doesn't? ) then you can add a nice twist to Mind Probe. My groups plays it as quite invasive (the target will be aware of it unless unconscious - and then only subconscious memories can be accessed) and the prober experiences the memories as though reliving them from the target's point of view. At the end, we enforce a Willpower test with a target equal to the number of net successes from the spell casting. Failure results in the prober picking up (for a short time at least) some of the definitive personality charactertics of the target, depending on what line of questioning was pursued. So the more you dig the more chance of being 'affected'.

The other interpretation we take is that the caster need not be the one who does the probing. It's an extra sense that he or she can just as easily assign to a voluntary subject he or she has touched. Which means mundanes can do the mind probing whilst the magician takes care of other stuff (with the sustaining penalty of course).