Things that disregard laws of nature, appearing utterly alien and inconceivable. Usually related to cosmic horror and Lovecraftian genres of horror fiction.
The first video game about Eldritch abominations was released on November 1992.
Generally these are being from somewhere deep from the cosmos that don't appear to use technology, or the technology they use is incomprehensible as such. Sometimes even alternate dimensions or realities, but often implied to exist in the depths of the cosmos. Note the word cosmos is favored in fiction that has them over deep space or similar.