Well here he is in the final stage of his transformation, resurrection. As a freshly turned zombie he might simply resemble a badly injured or sick person. It’s important to distinguish the difference. There was a great scene in The Walking Dead where Daryl was mistaken for a walker and nearly killed because he was exhausted and injured. We don’t want to kill the living and weaken our numbers so keep a sharp eye out. However if you’re in the middle of a full on outbreak, just off the guy. Better to be sure than to hesitate.
At this point there should be clear stages of dehydration and decay. Blood should be pooled in the extremities and it’s likely there will be an unbelievable smell coming from this guy. He will likely but not always appear, confused and disoriented but show signs of aggression towards any humans he comes across.
Finish him off any way you can, he’s a zombie and he’s going to eat you, if you don’t stop him.