Elvish Branchbender

Text:

: Until end of turn, target Forest becomes an X/X Treefolk creature in addition to its other types, where X is the number of Elves you control.

Rulings:

• 10/1/2007 The value of X is determined when the ability resolves. It won’t change later, even if the number of Elves you control changes.
• 10/1/2007 If you control no Elves when the ability resolves, the Forest will become a 0/0 creature and be put into the graveyard. However, since Elvish Branchbender is itself an Elf, the Forest will usually be at least a 1/1.
• 8/1/2008 A noncreature permanent that turns into a creature can attack, and its <img src="/Handlers/Image.ashx?size=small&amp;name=tap&amp;type=symbol" alt="Tap" align="absbottom" /> abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn’t matter how long the permanent has been a creature.