Monsters

Breath Weapon (Su): Either a cone of cold 20x20x20 feet long or a cone of paralyzing gas 20x20x20 feet long. It cannot use either breath weapon until 1d4 rounds later. Cold damage 2d8, Reflex half DC 14; gas damage Fortitude save (DC 14) or be paralyzed for 1d6+1 rounds.

Spell-Like Abilities: 3/day-polymorph self. A silver dragon's polymorph self works just like the spell, except that each use allows only one change, which lasts until the dragon assumes another form or reverts to its own (which does not count as a use of this ability). These abilities are as the spells cast by a 1 level sorcerer (save DC 12 + spell level).

Immunities (Ex): All dragons are immune to sleep and paralysis effects. All silver dragons are also immune to cold and acid.

Cloudwalking (Su): The dragon can tread on clouds or fog as though on solid ground. The ability functions continuously but can be negated or resumed at will.

Blindsight (Ex): Can ascertain creatures by nonvisual means (mostly hearing and scent, but also by noticing vibration and other environmental clues) with a range of 30 feet.

Keen Senses (Ex): Sees four times as well a human in low-light conditions and twice as well in normal light. It also has darkvision with a range of 100 feet.