According to the rules of Ghostbusters: A Frightfully Cheerful Roleplaying Game, something bad should always happen whenever a Ghost is rolled on the Ghost Die. The nature of this bad thing is left to the Ghostmaster's diabolical devices, and this is usually not difficult to do when it's the antagonist who rolls the Ghost. The Ghostmaster merely increases the effectiveness of whatever the antagonist was attempting or tosses another complication into the situation. But what happens when a Ghostbuster rolls a Ghost and the Ghostmaster can't be bothered to come up with another critical goof-up on the fly? I'm glad you asked, because there are two tables for just such an eventuality one for successful rolls and one for failed rolls. And here they are!
If You Succeed and You Roll a Ghost...
Roll 1D61. You do the thing, but then you take a pratfall.
2. You do the thing, but then you drop something you need.
3. You do the thing, but then you forget what you were doing for one round.
4. You do the thing, but then make too big a deal about it, reducing your Cool to 1 until you succeed at something without rolling a Ghost.
5. You do the thing, but then you break it, jam it, weaken it, or otherwise render it useless.
6. You do the thing, but must immediately make another roll to make the success stick.
If You Fail and You Roll a Ghost...
Roll 1D61. You also slip and fall. Spectacularly.
2. You also somehow manage to drop everything you are carrying.
3. You wander aimlessly, talking to yourself, until someone or something snaps you out of it.
4. You apologize excessively, reducing everyone's Cool by 1 until you succeed at something without rolling a Ghost.
5. You also render it (whatever "it" is) useless. Try something else next time.
6. You very loudly curse your failure, which attracts everyone's (and everything's) attention, blowing your cover completely. Everyone in your group is stunned by this display for 1 round.
Another method of addressing the pickle that is narrating the result of the Ghost Die is described in The Discretionary Ghost Die. Use with discretion.