Tar baby has become short hand for a situation better avoided than confronted.
It comes from a children's story in which the dark skin and seeming ignorance (caused by a lack of schooling) of slaves were explained by the idea that black children were baptised in tar, which made them dark and dumb.
Tarbaby usually falls between 'stovepipe', 'yardape', and 'spearchucker'.
The word 'tarbaby' is guaranteed to get you in a fight with a person of negro descent if it is overheard. 'Silverback' is also a good one.
"Ha ha ha! Your team has a tarbaby quarterback AND a tarbaby coach! Hahahahahahahaaaa. Good thing there's no swimming event in football!"