Pros
-Can you say: Book of the Moon?

 

Cons
-CRAPPY outside of that use

 

Ok, a small, and very annoying combo.

 

Lets just say your opponent has a APS (Jinzo) waiting for you, but he desides to attack with a lower monster (for this example, lets say its Bird Man/Harpies Brother).  He hits this little thing and you chain the effect with Book of the Moon/Book of Moon on APS.  Now Jinzo is facedown, making it legal for Bomb Bug, which destroys APS.  Yay.  Now you can activate that Holy Barrier-Mirror Force/Mirror Force you were waiting to use.

 

This card is at it's best in really really annoying deck types like Insects and anti-facedown combinations.

 

Now, this card is HORRIBLE when you don't have anything to combo with this card, but I have seen a very common situation where your opponent sets a monster then attacks.  Mostly by inexperienced players, but it happens sometimes.  Then again, I would much rather use a Emissary of Obliteration/Nobleman of the Crossout or Shield Crush [not in english], but in insect decks, it does have a limited use.

 

3/10- No deck should have this card in it unless you base alot against face-down monsters.
6/10- Devastatingly annoying when used properly.

 

-Zero