According to standard wisdom, six different nuclear burning stages, from hydrogen to silicon burning, can occur during the hydrostatic evolution of stars. However, several instabilities can lead to the mixing of layers with different compositions and produce non-standard composition mixtures. Those—when at high enough temperatures—burn due to nuclear reactions which are unimportant otherwise. We provide various examples of such occurrences, for different ratios of burning over mixing time scale. ©2001 American Institute of Physics.