That’s what happened on Halloween eve in Dublin, Ireland, when an AI-generated ad prompted a crowd to attend a parade that never happened.

Halloween revelers in Dublin felt trick-or-cheated after showing up in droves to a much-anticipated parade — that wasn’t actually scheduled.

A website promoting a fake Halloween parade in Dublin caused thousands to descend on the city center for an event that never was. Franz Marc Frei / Getty Many criticisms regarding the ...