jemandem einen Bären aufbinden

Literally: To tie a bear to someone

Example: “Er wollte mir einen Bären aufbinden mit seiner Geschichte vom Lottogewinn.” — He tried to pull my leg with that story about winning the lottery.

English equivalent: To pull someone's leg

Origin: The most linguistically grounded theory traces Bär here to an old Germanic root, bar-, meaning simply "a load" or "a burden" — "binding a burden onto" someone originally meant loading them down with something, quite possibly a lie. Once that older, narrower sense of the root word faded from everyday use, speakers reinterpreted the now-unfamiliar syllable as the ordinary word for "bear," the animal, through simple folk etymology, even though a literal bear makes considerably less sense tied onto someone's back. A separate strand of medieval storytelling may have reinforced the reinterpretation regardless: bears featured prominently in folk tales and fables of the period as figures of deceptive, often dangerous cunning, giving the confused, animal-based version of the phrase a ready-made association with trickery even after its original, more literal sense had been lost.