"Sister, I'm gonna smurf you up your smuf and then smurf all over your smurfs" -an enraged enchanted elder from the platform, magically turned into a smurf because kid brought in a Gargamel toy to the Hall.
Actually I think the urban JW legend goes that a toddler brought a papa smurf doll who stood up in the middle of the meeting, and announced "I'm sick of this shit" and walked out." Well, he's not dim.
The other one I remember, and this one was told around the hall by a woman that was wacko, was that a kid had smurf curtains, and one day the parents came into the room and the smurfs were doing a pagan dance around the kids bed.