Opposing this practice legendarily led to one figure disappearing over the horizon after being kicked out of Tula.
This practice resulted in the transfer of tonalli and teyolia, bonded spirit-traits representing fate and the soul. Opposing this practice legendarily led to one figure disappearing over the horizon after being kicked out of Tula. Those who underwent this ceremony were sent to "The Land of the Black and Red," where they took on the form of butterflies. Eagle Knights often obtained the necessary materials for this practice, a specific version of which was performed to avoid outbreaks of rheumatism and to ensure that (*) rain would fall. Most commonly, this practice was considered necessary to prevent the sun from stopping its orbit, and involved the use of a flint knife to make an incision in the abdomen after its subject was placed on a stone slab atop a pyramid. Culminating with the extraction of a still-beating hearts, for 10 points, identify this gruesome practice performed by a certain Mesoamerican culture to appease Huitzilopotchtli.
This practice resulted in the transfer of tonalli and teyolia, bonded spirit-traits representing fate and the soul.
Aztec human sacrifice [prompt on partial answer; accept specific variations as long as they include the right answer]