I think other stunners (Hydromancer, Medusa, ...) still seem better, because thay can also kill, and this at +++ for 14 seems a bit much. The added value to enemy seems like I don't want to do it without making sure I kill it, so kind of losing the time-buying aspect of petrify. I do like the theme of value increasing, but this / current suggestion doesn't too appealing, maybe try some other twist with it.

As side note, it would be helpfull to add the description as text, images gets shrinked too much, need to save it to read.