Nightmarishly Hard levels, also called owl levels, are levels officially marked to be a very difficult level by King. They are a proper subset of hexagon levels. It is usually the most difficult level in a given world, as each world is limited to one to five nightmarishly hard levels.
This feature is only explicitly shown on mobile. The level type color is hidden and changed to darker blue, which is ringed by a gold skull and a thunder cloud above it and Odus is marking. No Dreamworld levels are nightmarishly hard levels since Dreamworld had been removed over a year before nightmarishly hard levels were introduced.
In a mobile update in 2018, nightmarishly hard levels are implemented. They mark levels as "owl levels."
However, just like any other hard level, not all nightmarishly hard levels are usually the hardest. Examples are 1073 (the hardest is 1072).
See the full list of Nightmarishly hard levels.
- The equivalent in Candy Crush Soda Saga is "Ultra Hard level".
- Strangely enough, these levels are introduced earlier in the game than Super Hard levels.