SIZ and unusual biologies

[cappadocius]

I've been working on a BRP-based Pokemon campaign for a little while now, and SIZ works just fine for the more typical biologies, those Pokemon that are, more or less, animals.

However, I'm struggling with the appropriate SIZ assignations for the odd critters. For example, Bronzor, a solid metal disk that's 1'08" in diameter, weighs 133 pounds. SIZ 10 doesn't FEEL right for something only a little bigger than an LP. On the other side of the coin, there are the ghosts, such as Gastly, which is a gaseous sphere about 4 feet in diameter, but weighs two-tenths of a pound. SIZ 1 seems wildly misleading, and will significantly short gaseous entities on Hit Points.

Has anyone worked out SIZ tables for non-organic life forms? If not, does anyone have some good rules of thumb for densities greater or lesser than human norm? I vaguely recall CoC 4th or 5th edition talking about how SIZ is more properly a measure of volume than mass, but also recall CoC failing to give any spot rules for how to work that in practice.

Hit me with some BRP knowledge, folks. And please, no comments on how lame or not lame Pokemon are in *this* thread.

[seneschal]

"SIZ 23, I choose YOU!"

I had similar questions about Burroughsian Green Martians, who stand 15 feet tall but weigh only about 400 pounds, much less than they would on Earth, because of their less dense low-gravity body mass. Unfortunately, based on the answers I got in earlier threads, there aren't any such guidelines in the Big Gold Book either. Once you get away from humanoid creatures or critters that can be extrapolated from existing animal stats, you're reduced to guesswork. BRP just wasn't designed with such things in mind.

On the Gastly, however, you might be able to compensate with the super powers rules by buying up the creature's Hit Points beyond their "normal" mass-based total. For the Bronzor, you might buy up its DEX, Dodge skill or various defenses so that despite its human-level mass, it is extremely hard to hit because of its compact dimensions.

[fmitchell]

I had similar concerns when representing golems, robots, androids, cyborgs, and the like, which are approximately man sized but denser than humans. I came up with a few solutions:

• Non-organic beings have split SIZ, one used for reach/height/volume and the other for weight/mass/force. (E.g. Strike Ranks would use Height SIZ, while Hit Points would use Mass SIZ. Damage bonus might use an average, given that the momentum of a fist depends both on mass and leverage.) See also the Density Control superpower.
  
  
• Tougher creatures may have more Armor Points, to represent the durability of a titanium frame or solid stone. Conversely, more fragile creatures might multiply damage from some or all sources, or like skeletons have a chance to shatter completely based on the amount of damage done. Armor might also differ based on the type of damage, e.g. a golem might blunt a cutting or impaling weapon (e.g. an axe), but succumb to a crushing weapon (e.g. a sledgehammer).
  
  
• Some creatures may take damage in odd ways, like creatures in Call of Cthulhu, e.g. Mi-Go take minimum damage from impaling weapons, shoggoths take only one point of damage from any kinetic weapon. GURPS has a more complicated damage system, which multiplies hit points that penetrate armor, and different multipliers for different types of creatures: living (most things), un-living (mainly robots and zombies), homogeneous (animated statues and the like), and diffuse (sapient swarm, water elemental). One need not go that far, but, for example, decreeing that zombies and golems take no extra damage from impales makes sense.