You can only activate this card when your opponent declares an attack. Destroy the attacking monster.
*** *** ***
Today's COTD is quite possibly the most popular 1 for 1 trap in todays metagame. When it was first released, we still had cards like Raigeki running abroad, so we didnt really NEED to use this card, but once the first restricted list came out, this card slowly started to gain popularity. Before long the popularity basically snowballed to the point where it is now; at LEAST one copy is played in almost EVERY deck. Although it doesent GUARANTEE you protection (Cards like Mobius and V-Lord do NOT fear the armor) it can get you out of a tight spot.
Advanced Format 4/5