2018-01-19 : If the target creature is an illegal target by the time Crashing Tide tries to resolve, the spell doesn’t resolve. You won’t draw a card.

2018-01-19 : Once you announce that you’re casting Crashing Tide, players can’t try to remove your Merfolk to make it lose flash until you’re done casting it. If it loses flash after it’s been cast, it will still resolve if able.