Chromatic Star/Sphere and Tutors, also Necropotence

[kicks_422]

1. I have B floating, a Chromatic Star/Sphere in play (does it matter which one?), and a Mystical Tutor in hand. Can I somehow filter the B mana into U, cast Mystical Tutor for Yawgmoth's Will, then draw it with the draw from Chromatic Star/Sphere?

2. With Necropotence in play, if say I have 0 cards in hand then I pay 10 life to draw 10 at my discard phase, will I discard down to 7 cards or not?

[Cait_Sith]

1) You can with Star, but you cannot with Sphere. With Sphere the draw is part of the filter so you draw long before Tutor resolves. With Star the draw is a triggered ability. Filter the mana and respond to the triggered ability with Mystical. If you filter the mana as part of the announcement of the spell then the triggered ability will go on the stack above Mystical Tutor.

2) You'd discard down to 7.

[gnurbel2000]

1. You need a Chromatic Star because its draw is triggered so you can filter the mana and while the draw is on stack, you can cast the tutor. WIth a Sphere you ca't do it, because you have to draw at the same time as you filter the mana withot eing able to do something before you draw the card.

2. You have to remove the cards dow to 7 card, because you get the cards at the end of turn, but the discard down to seven is in the cleanup step.
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