Geancanach

The Geancanach (Gan-cahn-ock) is pixie-like in appearance, with huge eyes that curve upward on the ends and large pointed ears. They are always depicted as being very small, no more than a few inches in height, and having playful, if somewhat mischievous, smiles. They have small wings which do not seem functional, and they appear to move from place to place by dematerializing and reappearing quite rapidly. They may be mistaken for flickering lights or lightning bugs.

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Okay - I can see how these would be fun little creatures to have running around.  Love the mischievousness and the fire-fly aspect as well.