bjørnetjeneste

Etymology
, with reference to The Bear and the Gardener, in which a bear inadvertently kills his friend when trying to keep away flies.

The second sense is attested since 1992, and might be an allusion to the size and (perceived kind) disposition of a bear.

Noun

 * 1) A well-intentioned disservice.
 * 2)  A very great service.

Etymology
From, after a French fable; compare with 🇨🇬.

Noun

 * 1) a disservice, meant for somebody's good
 * 2) an unintentional ill turn