NCIS aired a Halloween adventure this week, with a mysterious prankster in the office and a mysterious explosion on an oil rig endangering those at sea.

The case's twists diverted the team from the real culprit throughout, in large part due to the fact that the first instinct is to wonder if terrorism is involved.

The always-enjoyable Diane Neal returned as Abby Borin, who was sort of offered Ziva's old spot on the roster, but will not be sticking around full time.

The prankster, meanwhile, remains at large.

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