The One-Eyed Blue Terror is a large blue flying ghost that was in battle with the Ghostbusters on the Twin Towers.
During a bust atop the World Trade Center, the One-Eyed Blue Terror nearly knocked Egon Spengler off the roof. Egon was about to fall to his death, but Winston Zeddemore came over piloting Ecto-2 to save him. After rescuing Egon, Winston used Ecto-2's cannon to shoot the ghost down, making it possible for the Ghostbusters to trap him.
Aside from flight, the One-Eyed Blue Terror can emit a laser beam from its eye.