Let’s look at the Mystic’s first ability. It’s an activated ability, which means that in order to be a mana ability, it has to potentially add mana to a player’s mana pool when it resolves, not have a target, and not be a loyalty ability. This one passes the test with flying colors.
What about the Mystic’s last ability? The rules for triggered mana abilities are a little different. They need to not have a target (check), add mana to a player’s mana pool when they resolve (double check), and trigger as a result of activating a mana ability (…nope). This means that the ability will go on the stack, and you’ll have to wait for your opponent to pass priority before it can resolve and put mana into your mana pool. You also can’t unmorph and trigger it in the middle of casting a spell, since you wouldn’t have priority at that time, and turning a creature face-up requires priority even though it doesn’t use the stack.
Today’s Rules Tip written by Jen Wong