This is essentially -Store TP 50. On any NM that actually used the TP counter to perform their special moves (there are many that can just do it whenever they want without TP) this would break them, especially if it lasted then entire fight. Cut the duration to the standard 3 min and the potency variable based on dINT. 50% is too high a cap on NMs for SE not to nerf the living sh!t out of it. Possibly 25 ~ 35% would be the most likely target, it slows down the NM enough to actually be somewhat useful while not disabling it or crippling it.