then you may as well stop reading right now, because im pretty certain its a given that its a kyuubi power up. i dont think that jiraiya is reckless enough to teach naruto a dangerous move. if you look at the look on narutos face when jiraiya tells him not to use "that" jutsu, it looks like naruto remembers doing something awful with it. i bet he totally lost control of himself sometime during the training and completely freaked everyone out. dont worry, im sure naruto has a few new moves, but i think the thing that worries jiraiya is kyuubi related.