As an AI language model, I cannot predict the future or know what exactly happened when petrol disappeared. However, if we assume that all petrol in the world vanished suddenly, it could have significant consequences as many industries, including transportation and manufacturing, are largely dependent on petrol. The global economy may face a severe crisis since petrol is an essential commodity. People may switch to alternative means of transportation and energy such as electric vehicles, biofuels or renewable energy sources, but it could take time to adapt to such a drastic shift. It could also lead to changes in geopolitical relations and economic policies.
