Cold Blooded is a physical defect that can be chosen at character creation for mutants to get 2 extra mutation points.
Your vitality depends on your temperature; at higher temperatures, you are more lively. At lower temperatures, you are more torpid.
Your base quickness score is reduced by 10.
Your quickness increases as your temperature increases and decreases as your temperature decreases.
+100 reputation with unshelled reptiles.
There is unusual behavior around temperature -90, where quickness jumps back up.