Mad Prophet has an activated ability that reads, “T, discard a card: Draw a card.” When activating an ability, all costs must be paid or it cannot be activated. Discarding a card is defined as moving a card from your hand to the graveyard. In this scenario, if you want to activate the ability, you must not only tap Mad Prophet, but move a card from your hand to the graveyard as well.

Remember that everything before the colon (:) in an ability is part of the activation cost, and everything after the colon is the effect of the ability. So if you can’t pay all the costs, you can’t activate the ability. If the Prophet’s ability simply said, “T: Discard a card, draw a card.” then you’d be able to pay the only cost (tapping the Prophet), and then do as much as possible as the effect resolves (you couldn’t discard a card, but you could still draw one afterwards). But unfortunately, that’s not how it works!

Today’s Rules Tip written by
Ronny Alvarado, Level 1 judge from Houston, TX