Black Mage's Rod There's a ton of support for this kind of deck and card in this set
Note how it triggers on enchantments entering the battlefield, not casting them, just like Archon of Suns Grace and Setessan Champion
It is always going to be there waiting for the spell you don't want it to hit
This card used to be super powerful when it was first printed, but it's still a scary creature to face on the battlefield nowadays, even if it's not the scariest creature nowadays
Because damage remains marked on a creature until the cleanup step or an effect removes that damage, nonlethal damage dealt to a creature may become lethal if you switch its power and toughness during that turn
Other ways to use the big mana value of split cards include Starfield of Nyx, Zur, Eternal Schemer, and Metallurgic Summonings