Do an Edna

(1) To tell a seemingly harmless story which has an appallingly repulsive and/or filthy ending;
(2) To be stunningly rude to someone.

(1) He described his new girl friend and ended by doing an Edna on us;
(2) The football hooligans did an Edna on the visiting team;
(3) I dared him to do an Edna and he did!