will-o'-the-wisp

But the little light version slipped through her fingers like a will-o'-the-wisp.

The independence referendum is the will-o'-the-wisp of the Scottish election campaign.

The lively, self-aware musical has such a will-o'-the-wisp quality that you fear it will disappear if you attempt to fence it in.

Chasing will-o'-the-wisp planners, judges and environmental activists is mere skirmishing.

Dananjaya, a will-o'-the-wisp 18 year old from the southern suburbs of Colombo, was given his international debut.