I have a coworker that will take projects out from under you and do all the work themselves if you ask to collaborate with them. It happened twice, one of them he out right took all the credit and handed me peanuts. The person knows this so they try to keep you involved by having you review their work, which is usually pointless because they’ve already done all the work and there are no alternatives or caveats to consider. I will never work with them again even though they do good work and are sharp, purely because they’re a control freak and it slows everyone down.