A beautiful gown, a thunderous musical performance, a shocking piece of news, or a deadly disease could all be described as foudroyant, meaning sudden, shocking, and intense.
Foudroyant is a French loanword coming from the word foudre, meaning "lightning." In French it can mean "rapid" or "devastating," but in English, something foudroyant is so dazzling or stunning that it's overwhelming in the way that a crash of thunder or bolt of lightning would be. It has a special meaning in medicine: it describes forms of diseases that attack very quickly and very severely.