- Not available on that edition (the reason is in the tooltip)
- Depends on the setting, your class or another addon (details in the tooltip)
What it does
Checks if the creature type of the unit specified, such as Beast, Demon or Undead, is the one you choose.
Why you might use it
Checks a unit's creature type, such as Beast, Demon, Elemental, Humanoid or Undead. Use it for spells that only work on certain types: Banish on Demons and Elementals, Shackle Undead, Exorcism or Turn Undead on Undead, Hibernate on Beasts and Dragonkin, or to skip damage over time effects on Totems and Critters; it also works as a switch condition. On Retail and WoW Forever the game hides the creature type of NPCs outside your group, so there it is usually unavailable for enemy NPCs.
Example
your target's creature type is Demon
Settings
What each setting in the condition editor means, from the game's own help.
Unit - The unit this condition uses as the target of comparison.
Creature Type - The creature type of Unit. This can be used to create conditions that are restricted by creature type (eg. Banish).