The Big Baby Ghost is a nine foot tall ghost loosely resembling a crying baby in a diaper.
The Ghostbusters were called to Pumpernickel Kindergarten after a Big Baby Ghost manifested. It seemed to continuously cry ectoplasm tears from its four eyes. It held Peter Venkman upside down. He declared baby ghosts were the worst. Winston Zeddemore thought he said animal ghosts were then recalled it was pirate ghosts then witch ghosts. Egon Spengler reminded him of the ghost of Peter's high school principal. Peter got tossed. Peter clarified he didn't like ghosts. The Proton Pack malfunctioned when they tried to fire them. Egon concluded the ectoplasm got into the LaMarche Boards so the pack couldn't discharge properly. The ghost slammed its fists on the ground. Before they could regroup, another company named Spooks Away arrived. Brad generated a hologram of a baby mobile to draw the ghost's attention while Kiki used a self-retracting plasma snare to capture it. It was added to the Prediction Engine, became part of the Mega-Entity, and was freed by the Ghostbusters.