The existentially insightful animated video series Kurzgesagt explains how a giant battle between galactic matter and dark energy can, and most probably will, ultimately destroy the universe in one of three different ways. Not one of these options sounds pleasant in any way.
The universe is going to die one day, and a fight between two titans will decide our cosmic fate. On one side of this galactic battlefield, we have all the matter in the universe; on the other side, empty space infused with dark energy. Whoever wins will kill the universe in fun ways.