Some people love a harmless prank. Olga went for pure prankless harm. Bride plans an all black wedding, spells it out for everyone, lines her bridesmaids up looking sharp and matching. Olga ducks back into the room with a fake makeup excuse, and suddenly everything feels a little too quiet.
Five minutes before the ceremony, Olga shows up in a bright tight red dress that could guide planes in for landing. She tells staff the bride okayed it, then plants herself in prime viewing range. Bride walks down the aisle, finally looks up from her husband, and there is that one screaming red spot in a sea of black. Not a slip, not a mix up, just calculated main character energy.