What are super normal profits made by companies due to an unprecedented event, as indicated in the para above, known as?

Windfall gain (or windfall profit) is an unexpected gain in income from an unforeseen source/event. Windfall gains may take place due to sudden steep rise in prices of a commodity or extreme shortage of a resource, asset or product. For an individual, windfall gain could be a sudden spike in income due to one-time events like inheritance of property, money gained on selling property when its prices increase dramatically, etc. Windfall gain may also refer to gains from winning a lottery, betting income etc. A windfall tax is a one-off tax imposed by a government on a company on such windfall gains, which is over and above the normal rates of tax.