大乘起信論義記 3.449

3.449

或有眾生無善根力，則為諸魔外道鬼神之所惑亂，若於坐中現形恐怖，或現端正男女等相。

There may be sentient beings lacking the power of wholesome roots who are confused and disturbed by demons, non-Buddhists, ghosts, and spirits: while sitting, these may manifest forms to terrify them, or manifest handsome and beautiful male and female forms.