I believe it would increase the drain by 2, unless you allowed the player to add more restrictions than the invisibility spell normally has. Note that the original spell does not have any restrictions (such as voluntary) and is LOS. You can limit how efficiently the character can make the spell thereby making the drain (F/2)+3. Not awful for what you get, but at least higher.

Keep in mind that improved invisibility (and other illusion spells) are not simple success tests. Illusions are resisted by living targets and must overcome the object resistance of the technological system it's attempting to overcome. It's true that this is not *too* difficult, but you could roll for players (similar to rolling perception or infiltration for them). Then give them a test for an idea as to how well they think they did (pg. 174, BBB).



If that isn't enough then you could apply the additional drain modifier for "concealing" to every additional sense he wishes to conceal. It's not the letter of the rule, but it seems reasonable if you think you'll need to limit the spell in some way. You can point out that they could always just cast 3-4 separate spells to do the same thing.

Undetectable by pressure plates? What's the thought behind that one?

I'm all for new spells, but I never liked this one. If you want to play an undetectable mage, you can already combine invisibility, mask, and silence spells. Combining everything to one spell would at the very least have a (houseruled) high drain.

Still doesn't fool watcher spirits or dual-natured watchdogs, though.

By making imp. invisibility effective against all senses (rather than simply the one sense described in the RAW spell), hence it also renders the mage invisible to touch, a form of pressure. I don't want to get into the details of how it works, or resurrect the invisible flashlight thread, but it sure seems like it would negate the efficacy of pressure plates.

My concern for this particular spell comes from the fact that you remove a -ve modifier on the RAW spell (one sense only), and the drain can easily be dropped back to the same or lower by limiting the target. Granted it doesn't fool dual natured observers or watchers, but neither did the imp. invisibility spell.

It's bad enough that invisibility is utterly trumped by imp. invisibility, without making another invisibility spell that renders both the RAW versions obsolete.

I can't really wrap my head around that... would that mean that the target of the spell becomes intangible and incorporeal? Would his/her punches go through a person, or just not have any effect?

I guess I see pressure plates reacting to the force of a mass, not sensing by touch.
Touch, for me, would be sensing textures. Other reactions would not be philosophically categorized as sensing, though the physical medium is the same.

Back to the general question... I share your concerns, and would not allow the spell. If pressed, I'd make it have a high drain, or throw a book at the requester.

It doesn't actually take much to spot a party magically. A force 2 spirit bound in a vessel can always auto buy a single success to assense people moving through an area. it doesn't matter how good the team is, if they have to move past a force 2 spirit each guarding the only two doors in the complex it might be hard to get past them. However what is a pain about a spell like that is it is really pass or fail. Either you set up situations where they can't really pass through, or it is a cakewalk. Personally I would table that spell for the only reason that as a GM it will be hard to create dramatic suspense for the characters. I would also tell your players this, because it now the only option you have as the GM is sink or swim. An easy win, or there is just no way you can get into that warehouse without being spotted.

Oh... also I would like to add it is the wiggle room in spells that can get you. Sometimes there are reasonable spells that you might want to use in a slightly unconventional way, and that generally speaking slows down a game. If an action undertaken is more clear cut like applying a skill to a situation I find just rolling some dice and depicting the situation as the dice falls is fairly simple... However I have found the SR magic to be somewhat trickier then the games skill set and when anyone tries to use it in a somewhat complex way it seems to slow the game down to a crawl and detract from the RP.

Stacking the OR makes the shapechange spell a more viable choice. However if you can't use your equipment it would make foci an odd thing if you could use them since it would all be absorbed. It would make the character duel natured w/o really being duel natured. It would also be very odd to handle the way the spells would work and how you would be able to cast into the foci when it is a part of you. Personally if I did have to rule I would say that you can't actually use any equipment, and that only cyber/bio ware (for the most part) is allowed as your character would have had to pay essence so it is technically a part of the characters body. Cybereyes would not give you vision mods though to name just one. I would however limit the body and strength boosters of any cyber or bio the character has so that when in shapechange mode it can't be a freakin' super rat.

Oh yeah the question on bio drones is you could rip out a dogs brain and rewire it to basically be a puppet with a kind of controlled sentience (almost like the crazy cyber dogs from Snow Crash.) It is a way to make a drone a rat and then back into a crazy killing machine again w/o tripping too many alarms.

Biodrones I see as less of a problem, since all that implantation makes them crazy anyway, and if you cast the spell it's 'ware is absorbed and rendered non-functional. Then you can't rig it and the animals craziness is released. I would rule it as certainly going beserk, and attacking everyone around it - especially the casting mage who is touching it.

Also it would be a pretty interesting run if you took a bunch of biodrones and turned them into rabid dogs. Move them through the city by driving and fronting as a dog catcher.

"Yeah... I wouldn't touch them.... they are going to be incinerated soon, and they might be carrying an awakened strain of something."

However that being said brains in a jar are not cyberzombies. It would be pretty difficult to program a bio drone, but just a rat brain living in a BTL rat paradise might be an interesting way to keep it sane although it would be quite hard to get it to work because of the essence hole. Might not even need to be connected to the drone, but just have the drone be the brains equipment surrounding it.

It would be pretty easy to jack a 'borg driven by a rat brain in a jar tho. Rat's aren't known for their high level intellectual capacity, so I doubt they'd be much cop at hacking.