[johndallman]

Cold-Blooded [-5 or -10] is an exotic physical disadvantage, and not realistically possible for humans; it should only be a racial disadvantage, unless there’s a lot of bioengineering involved. It appeared during the 3e period, apparently in GURPS Uplift.

Your body temperature varies with your surroundings (although it will always be higher than your surroundings in practice). This has some advantages, since you have +2 to HT rolls to resist the normal effects of high or low temperatures, and only need a third as much food as warm-blooded creatures, but you lose DX and Basic Speed below a “threshold temperature” which determines the disadvantage value: [-5] for 50°F and [-10] for 65°F.

Once you’ve been in an environment below your threshold for 30 minutes (or an hour if you have any degree of the Temperature Tolerance advantage), you suffer -1 each to DX and Basic Speed for each 10°F below your threshold. You recover at a point each of DX and Basic Speed per hour in a warm environment, or twice that speed in a very warm climate. I presume you don’t lose additional fractional Speed for the DX reduction.

Freezing conditions are worse: in an environment below 32°F, at the time you suffer DX and Speed reductions, you also need to succeed in a HT roll (warm clothing gives +2) or suffer a hit point of damage. I presume this is injury, rather than damage, and that you don’t suffer it every half-hour, but this is nonetheless a really bad disadvantage for a polar exploration game.

Cold-Blooded shows up on templates for appropriate creatures. Bio-Tech reckons it’s a necessary side-effect of equipping humans with gills, requiring a lot of biochemical re-design. And that’s about it for mentions in GURPS supplements. It’s a necessary disadvantage for specific kinds of creature, but not a very interesting one.

Does anyone have an idea for making this interesting?