This is the exhaust backfire from a motorcycle exhaust. The picture was exported from a video since capturing the flame in a picture was nearly impossible. The flame would only last for a fraction of a second. The bright blue and orange color comes from the gasoline and ethanol that is being burned. In the flame’s flow, you can see how right after exiting the exhaust, the flow is laminar, then soon after the flame expands. The flow also shows some of the changes in flow from the exhaust over time, where the big blob of flame depicts a time when the flow was slower, maybe the time period between two combustion cycles in the motor.