Yeah, I've heard about it in relating to the foam (foot)balls. If you nerf something, you make it weak. Maybenot get rid of, but get make them weaker and less effective. You'll sometimes hear it about MMORPGs in the context of character classes. Sometimes the players feel that a certain class is much more powerful than others and want them to be weakened or limited, in which case you can say that class got nerfed. Or maybe another class gets upgraded, and the imporvements mean that another class is significantly weaker in comparison. In which case you could say the existing class was nerfed by the upgrade.