For some reason, despite putting what you (very helpful) people showed me, losing fingers/toes and possibly other body parts results in the creature bleeding a material that isn't there at all; bleeding vacuum, I suppose. It's not related only to nails, since slicing off the foot of a skeleton causes said vacuum to leak out. It seems to be inconsequential, but it adds unnecessary detail. I may or may not have done something wrong.
I also assume skeletons being horribly weak to dragonfire being intended, given that they're solid bone with no homeotherm?
Have you noticed any puddles of said vacuum or is it that it says the creature is bleeding? If a tissue has any vascular value and is damaged beyond bruising it 'bleeds' an amount based on vascular value. If vascular value is 0, it doesn't bleed but still displays the status. (Based on extensive shenanigans in 34.x).
The way to disable this is to fully redefine the tissue without the vascular token.
[TISSUE:BONE]
[TISSUE_NAME:bone:NP] Whether it has a plural depends on exact part
[STRUCTURAL]
[CONNECTIVE_TISSUE_ANCHOR]
[TISSUE_MATERIAL:LOCAL_CREATURE_MAT:BONE]
[RELATIVE_THICKNESS:2]
[HEALING_RATE:1000]
VASCULAR:3 -----removing brackets is a method of commenting out a token
[PAIN_RECEPTORS:50]
[CONNECTS]
[TISSUE_SHAPE:LAYER]
[SETTABLE]
[SPLINTABLE]
Also note that nails do not have a vascular token normally which is why having your nails smashed in vanilla doesn't cause bleeding. Also, dragonfire is the bane of existence to everything that isn't [FIREIMMUNE_SUPER]. Even creatures that are fixed at a certain temperature aren't immune.
What is the upper limit for the [BODY_SIZE] token?
Don't think there is a limit, as far as I know.
If this link is accurate, the max size for raw creatures is 100,000,000. 2,147,483,647 is a limit that comes from variable types. (((2^32)/2)-1)
Also, body size is a volume - it is in cm^3. For standard material creatures, you can sort of substitute weight (grams).