Used as a way to tell someone that they are stupid. Can also be said as "Come from Bush."
context: When a reporter asked a resident of a third world country about how it is like to live there, he asked a man how he lost his leg. The man who was missing a leg simply replied: "we don' know who did it but all we know is that they come from bush and go BOOM! BOOM! BOOM!"
Jake: "So what is it like to live here in Uganda, I see you lost your leg."
abbo: "we don' really know wah happened, all we know is dat they come from Bush and go BOOM! BOOM! BOOM!"
Teacher: "What is 2+2?"
You: "5"
Teacher: You Come from Bush.