There are hundreds of different creatures in Zangband each of which poses a unique challenge to the adventurer.
Many monsters have the same letter symbol and sometimes color on the screen.
You can often determine some information about a monster based solely on the color it is described as having, like 'a White Dragon'. By being cold-based, we mean that the monster has either melee, magical or breath attacks that are cold based. Unfortunately this rule is applied somewhat inconsistently and there are several notable exceptions so don't be surprised. If that 'Green' monster spits acid at you. Note that this rule cannot be applied to the actual color a creature is displayed as but only to a color in its name.