Several theories exist regarding what happens when the screen blanks out, following the short teleport-like move by the user.
One version has it that the souls of both victim and user are momentarily teleported to another realm where they are attacked by demons of their past, hence the inherent danger it purportedly places on the user.
A second theory suggests that the user momentarily enters a frenzied state, delivering rapid attacks equivalent to upwards of 15 Hadoukens (chi bursts) at point blank range. This is demonstrated particularly well in Street Fighter IV. In it, multiple purple blasts resembling Akuma's regular hadoukens flash between Akuma and his opponent when he performs this technique.