Shifted abilities are the special powers, imitating those granted to creatures, which are given to player characters assuming a polymorph form. Shifted characters make use of these abilities as if casting a spell (which, depending on the ability, may result in triggering an attack of opportunity) and use the spell radial to cast the ability. These abilities have infinite uses unless specifically restricted by the spell script.
For many shifted abilities, shifter level is used for determining the results of the ability (e.g. damage and DC). However for several abilities — particularly those that cast normal spells — damage and DC are determined by caster level, with the ability considered a spell cast by the character's initial class (the class taken at character creation), and even spell focus feats are applied. That class' primary ability modifies the DC; the primary abilities of the possible initial classes are listed in the below table for reference.
If a spell from a spell book is quickslotted and the character polymorphs to a form that has that spell as a shifted ability, then he may use the quickslot to activate the shifted ability. In this case the caster level and DC are determined as if the character was casting the spell from that spell book as normal — even any metamagic specified in the quickslot applies. Spell slots will not be consumed for these castings.
Shifted abilities that correspond to player spells are fully compatible with the magical crafting feats (scribe scroll, brew potion, and craft wand). If the effective casting class does not normally cast spells (i.e. barbarian, fighter, monk, or rogue), then scrolls will be scribed as if the character was a wizard and wands will have no class restrictions. (Potions do not depend on the casting class.)
Shifted abilities that do not correspond to player spells will not cancel expertise mode, even if the module has turned on the switch to disable expertise mode while casting. Abilities that use a standard spell script are subject to this switch, though.
Shifted abilities are normally not available to non-player characters (NPCs), as the game engine fails to register such abilities for them (to the extent that a custom AI would need to determine which abilities should be available based on the polymorph type then "cheat-cast" them, if their use was desired). Dungeon Masters (and players in the case of familiars) who possess a polymorphed NPC can still make use of its shifted abilities through the graphical user interface, though.
See also: Category:shifted abilities