Defender Prevent all damage that would be dealt to this creature by creatures it's blocking. This creature can't be the target of spells that can target only Walls or of abilities that can target only Walls.
2004-10-04
Can be targeted by a modal spell that can target a non-Wall in one of its modes, even if it has a mode that targets only Walls. That spell can, in theory, target a non-Wall, so it is not a "spell that can target only Walls".