Aberrations are a type of monster in D&D 5e that defy the natural order of the world. They are often alien, bizarre, and terrifying creatures that have strange abilities and anatomy. Some of them are ancient relics from a primordial era, while others are incomprehensible beings from the future or the Far Realm. Examples of aberrations include aboleths, beholders, mind flayers, and slaadi. Aberrations are usually hostile to other creatures and seek to dominate, enslave, or destroy them.