Mood Slime

Mood Slime was a form of ectoplasm created by Vigo the Carpathian. "Mood slime" (as it was nicknamed by the Ghostbusters) reacts to emotions, enabling it to animate objects and empower ghosts. Mood slime charged with negative emotions- anger, particularly- empowers evil ghosts and infuses objects or people it touches with evil. Mood slime charged with positive emotions- joy, particularly- can animate objects to dance and move, as well as infuse people and objects with good.

Vigo planned to use a river of negatively charged mood slime to empower his resurrection. However, in the end, it was positively charged mood slime, used by the Ghostbusters, that defeated him.