Mindstealer reads "Whenever creature in opposite slot attacks it deals damage to self instead of Mindstealer"

 This ability doesn't interact correctly with Hydra, Lightning Cloud, or Forest Sprite.  Example: Hydra attacks when Mindstealer is in opposite slot.  Hydra takes 3 damage and deals 0 damage to opponent and all of his creatures.  By the way Mindstealer is worded, Hydra should have taken 3 damage and dealt 3 to everything except the Mindstealer.

 If Mindstealer is intended to negate "attack all" creatures entirely, then the wording should be changed to something like "Creature in opposite slot becomes a wall and takes damage equal to its attack each turn"