Look one's worst(Her lips were brightly scarlet, and with reading light behind her she well knew that she did not look her worst. Theatre, W.S.Maugham olgaglu)
worst-case scenario(A worst-case scenario is a concept in risk management wherein the planner, in planning for potential disasters, considers the most severe possible outcome that can reasonably be projected to occur in a given situation. Conceiving of worst-case scenarios is a common form of strategic planning, specifically scenario planning, to prepare for and minimize contingencies that could result in accidents, quality problems, or other issues. WK Alexander Demidov)