Should i take my coworker up on his job offer?

My coworker recently told me he moonlights doing an online job while working our normal job. I asked him what he does and he said that it's hard to explain but there's a powerpoint that explains when i get hired. He said it's all legal and we get paid $10 an hour and pay goes out every week. He showed me he's made an extra $250 this week on an excel spreadsheet. I think it sounds like a great opportunity/s

Anyway what flavor of scam do you think this guy is part of? I'm thinking mlm because he's trying to bring others into the fold, but I heard him tell someone else theres a fee to join, and that screams pyramid scheme.