What happens if I cast Power Sink on Scragnoth?
Scragnoth just says that it can’t be countered while it’s being cast; this doesn’t stop interrupts from targeting it, or from having their other effects. For example, Power Sink would still force the spell’s controller to tap mana, even though it’s incapable of countering Scragnoth, and Arcane Denial would still allow players to draw cards.
