Protuberance is a funny word that means a thing that protrudes or “sticks out” from something else. For small meteoroids, 90% of the mass is lost to ablation as they come through the Earth’s atmosphere. If a stony meteoroid had a protuberance in space, the protuberance would be the first thing to break off or ablate away as the meteoroid passes through Earth’s atmosphere.
If you have a rock with a protuberance or other features that sticks out in positive relief, then it is not a meteorite.
All of the photos below were sent to me by persons asking if the object was a meteorite. All have protuberances so none is a meteorite. Also, none of them has a fusion crust.