5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a psychedelic drug known for its uniquely profound effects on consciousness; however, it remains unknown how it affects the brain. We collected electroencephalography (EEG) data of 29 healthy individuals before and after inhaling a high dose (12-mg) of vaporized synthetic 5-MeO-DMT. We replicate results from rodents showing amplified low-frequency oscillations but extend these findings by characterizing the complex organization of spatiotemporal fields of neural activity. We find that 5-MeO-DMT radically reorganizes low-frequency flows, causing them to become heterogeneous, viscous, and nonrecurring and to cease their travel forward and backward across the cortex. Further, we find a consequence of this reorganization in broadband activity, which exhibits more stable low-dimensional behavior with increased energy barriers for rapid global shifts. These findings provide a detailed empirical account of how 5-MeO-DMT sculpts human brain dynamics, revealing a set of atypical cortical slow-wave behaviors with significant implications for neuroscientific models of serotonergic psychedelics.