The Crawling Chaos by H. P. Lovecraft and Winifred V. Jackson

A man takes an experimental drug and finds himself slipping into a nightmare realm that mirrors the horrors of reality. As he travels through apocalyptic visions of war, suffering, and death, he encounters a presence that seems to feed on human misery. The line between dream and waking life blurs, drawing him deeper into madness. The plot follows his descent into this crumbling world until he confronts the entity known only as "the Crawling Chaos." A surreal and disturbing journey through chaos, addiction, and revelation.