Associating Invisibility

Susan Richards goes
unnoticed while on the
prowl.

So there's been a lot of discussion of dissociative rules and all that Crap lately, which reminded me of one of my least favorite dissociated rules of D&D that I'm aware of.  I'm talking of course about invisibility.

More specifically, the rule that says that an invisible character immediately becomes visible upon initiating violence.

Why on earth would the forces of magic all of a sudden sprout a big hippie beard, fire up the patchouli-scented incense, and do their best yogi-pose as soon as an invisible character decides to garrote someone?  There's no similar rule for polymorphed beings entering combat, nor for the charmed, strengthed, featherfallen, etc.  Why the inconsistency?

Famous invisible people
of literature.

My assumption has always been that it's because our Founding Fathers considered remaining invisible during combat to be too much of an advantage, so they bolted on an external (dissociated) mechanism for leveling the playing field.  But it's a sucky one, especially when one considers the options available in literature, most famously in the writings of H.G. Wells and J.R.R. Tolkien.  Please read on:

If you really want to associate the effects of invisibility, our man H.G. is the way to go; only your body is invisible, anything which is not attached directly to your epidermis is going to be seen.  Which is why the invisible man walks around dressed like a mummy all the time.  That means that if your party wants to turn inviz to sneak past the guards, they gotta strip down to their goods, which might lead to this type of scenario:

Player:    I strip down and turn invisible to sneak past the guards to the Baron's bedroom. 
DM:       Once inside the chamber, you see a large, luxurious bed which is occupied by the baron and his wife who are sleeping soundly under a thick, cozy feather bed.  There is a fireplace, but the fire in the hearth has gone out and the wooden shudders on the windows do little to prevent the wintry drafts from chilling the room to near freezing temperatures. Your feet are icy from walking on the bare stone floors of the castle and though you are invisible, you don't need to see your naked flesh to tell that it is covered in goosebumps; you are beginning to shiver uncontrollably.   Did I mention that there is plenty of room in the bed for a third? What do you do next?

...which might lead to far different results than intended.

In addition, how far do you go with the associating?  Would an invizible Mr. Huge Ruined Pile look like a mobile, man-shaped mural?

In The Hobbit, Tolkien's take on invisibility is a bit more user-friendly.  Bilbo, thankfully, did not need to strip to his hobbit-sized giblets to take advantage of the invisibility conferred by the one-ring-to-rule-them-all, but when he whipped out Sting to slash the spider webs, the sword was fully visible.  And, as I recall, ring-wearing Bagginses were also said to cast a faint shadow, though I can't be bothered to look for the reference at the moment.

I think right here you have the beginnings of an effective leveling mechanism:

• the presence of an invisible being is marked by a slight visual anomaly, and 
• anything held in the hand is going to be visible.  

I think I'd take it a bit further and say that anything that extends beyond, say, 3 inches from the person's body, would become wholly visible i.e., that whole sword is visible including the hilt, not just the part that extends beyond ~3" from your hand.  Sure, this is a dissociation of sorts, but it's one that I can live with cuz it makes for a cooler image.

By this rule, any handheld item larger than a mid-sized link of sausage would become visible including swords, shields, staffs, but also non-handheld items like great helms, loaded backpacks, cloaks, wizard hats, pointy elf shoes, etc.    

So you're fighting in combat, everyone can see your weapon and the aforementioned visual anomaly--which, in my mind, is somewhat akin to the shimmery distortion that was apparent when The Predator was hassling Conan back in '87.*  That makes invizzos a lot easier to nail down in combat; let's say attackers are -4 to hit, even less if invizzo-dude is fighting 2-handed, using a shield, or is fool enough to be wearing a cloak or a backpack.  If he's doing all three, then he's pretty much given it all away; give 'em a -1 to hit  and that's it.

*And, of course, invisibility would also be useless against infravision--unless you cover yourself in mud. 

But what about invisible MUs blasting off spells from the 2nd row?  What's to make them less "unfair"?  Well, beside the aforementioned wizard hat ruling, what about this: when casting spells, the interaction of the aura of invisibility with the incoming magic of the new spell combine to create a magical reaction which causes invisible spellcasters to glow for the duration of the casting time of any spell and leaves a faint after glow for the remainder of the round; any attacks made against them are at +2.

That's an invisibility rule I could live with.  You have to treat invisibility a lot differently; no more hiding an entire party in a bag of holding which the invisibled thief then picks up and sneaks out the dungeon with.  In order to remain invisible, a character is going to have to ditch a lot of gear, making it useful only in certain situations.