The ex-"Survivor" star made a public appearance last week in Johnston City, TN -- where he got hired to show face (and muscle) at a place called Mouse's Ear ...  where exotic dancers are normally onstage, only here ... it was amateur 'Wrestlemania.'

Indeed, you can get a sense of what Jonny and co. were up to in these videos we obtained. He's very much playing the heel in front of the crowd, while the two "wrestlers" opposite of him -- Bam Bam Bundy and Lucky Larson -- are talking trash ... wondering how he's making dough these days post-"Survivor."

JF didn't take that too kindly, as it turns out ... 'cause he ended up hitting both of them in the back with the strip club equivalent of a folding chair -- namely, a freaking TIKI Torch!

It's pretty goofy, and obviously, no one was hurt ... but this is something we might start to see Jonny do more regularly. Funny enough, he actually has dabbled in the wrestling world for years now (even pre-"Survivor") ... and is a huge fan of the sport.