NCF – Extended list of Neutral creatures.

I've been playing the original game since almost its release, and I've never noticed this effect. Which unit has this skill by default?

As far as I know, three abilities from the game weren't used:
- Crystalline Scale (it works properly and isn't overpowered – I don't understand why they decided not to use it)
- Flame of Vengeance (if it's slightly reduced, it's a perfectly adequate ability – I also don't understand the reason for not using it)
- Horrific Visage (it's roughly equivalent to the ability – Etherealness; overall, it can be given without disrupting the balance, so I also don't understand the decision not to use it).