This card doesn’t seem too great in standard, especially considering that in still overloads you even though it’s cast by the minion, which is absolutely ridiculous.
If we compare this to Kazakus, he was good because he allowed you to choose the power level of the potion, and allowed you to possibly cast the potion on the same turn. Also, you more often than not knew what you would be getting from Kazakus, but this time it is totally random. With this card you’re paying 7 mana to have a small chance to react to the next turn, and in a lot of situations is too slow. If the meta slows down and becomes more control orientated then it may see some play as one of those cards you throw down on an empty board for late game value. It has potential overall, especially if any new powerful shaman spells are released to synergise with it, but then again, I don’t think I’ve ever seen many viable control shamans, and I’ve been playing since the game was released.
It’s also pretty poor that you can only choose one, or maybe even no target spells, as those are arguably the best shaman spells. With the current shaman spells available I think it’s safe to say this card sucks balls.