Playing on their trickster nature:
* A mischievous sprite, flitting through the forest.
* A phantom of the woods, whispering promises of gold.
* A shadow of a dream, disappearing as quickly as it appears.
Playing on their connection to gold:
* A golden glint in the emerald green.
* A glimmering spark, buried deep beneath the earth.
* A whisper of fortune, hiding at the end of the rainbow.
Playing on their mythical nature:
* A legend whispered on the wind.
* A creature of folklore, born from dreams and stories.
* A fleeting glimpse of magic, tucked away in the ancient woods.
Beyond metaphors:
* A mischievous fairy with a pot of gold.
* A small, powerful being with a knack for hiding.
* A symbol of Irish folklore and magic.
The best metaphor depends on the specific context and the message you want to convey.