As far as I can tell, some bored person came up with them around 1850 and everyone decided to indulge him. It's a flock of owls (except they're loners, so that's especially stupid)
There's a subtlety in the rules about which attacker wins; the winning attacker is the first one to post a clue whose intended answer is the defender's word -- even if another attacker's clue for the same word is contacted, passed, and solved first. — Gareth McCaughan ♦Jun 13 '17 at 19:43
