There are many different types of spells that do a myriad of things, from blocking incoming attacks, to healing damage, to killing your opponent's creatures, and much more. (magic.wizards.com)
As soon as you see that an enemy is about to attack, you need to enter this mode and automatically block all incoming attacks. (segmentnext.com)
Players can throw the shield, charge at an enemy with it, and of course block incoming attacks. (gamerassaultweekly.com)