Turn to Frog | Magic: The Gathering
Formats Turn to Frog is Legal in
Official Oracle Text for Turn to Frog
Official Rulings for Turn to Frog
9/22/2011 : Turn to Frog overwrites all previous effects that set the targeted creature's power and toughness to specific values. Other effects that set its power or toughness to specific values that start to apply after Turn to Frog resolves will overwrite this effect.
9/22/2011 : Turn to Frog doesn't counter abilities that have already triggered or been activated. In particular, there is no way to cast this to stop a creature's "At the beginning of your upkeep" or "When this creature enters the battlefield" abilities from triggering.
9/22/2011 : If the affected creature gains an ability after Turn to Frog resolves, it will keep that ability.
1/22/2011 : Effects that modify the targeted creature's power or toughness, such as the effects of Titanic Growth or Glorious Anthem, will apply to it no matter when they started to take effect. The same is true for counters that change the creature's power or toughness (such as +1/+1 counters) and effects that switch its power and toughness.