Putting a P/T boost and trample anthem on a huge 5/5 with haste for the top end of your creature deck and jumping into combat just makes sense, so much so that Wizards has since printed toned-down versions like End-Raze Forerunners and Demolisher Spawn
When the spell or ability resolves, it checks the targets to make sure theyre still legal (that is, theyre still there and they still match the requirements of the spell or ability)
Similarly, the power of the creature attacking you is checked only when MacCready's second ability triggers
Since then, sales have remained strong each day
One thing to note before diving into these cards, however, is that they feature a pretty significant departure from past enchanted artworks
But with this, I can just cast it at the end of someone's turn, draw it, and cast it with all of my mana free