Creature of equity
A kind of fantastical intellectual artifice that, from time to time, the courts of chancery imaginatively deploys in salvation of one of those little old ladies who populate their reports. For example, estoppel or a constructive trust.
Not to be confused with a creature of Equity, such as a pantomime dromedary staffed with unionised actors, however similarly restorative such a sight might be to such a little old lady.