Cheapest priced copy (Fifth Edition): $0.35 at Card Kingdom, near mint, their price list as of .
Cloak of Confusion 
Enchantment — Aura · Common · Fifth Edition · #151
Enchant creature you control
Whenever enchanted creature attacks and isn't blocked, you may have it assign no combat damage this turn. If you do, defending player discards a card at random.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
2 printings · $0.35 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Fifth Edition | 151 | Common | $0.35 | — |
| Ice Age | 117 | Common | $0.35 | — |
One ruling from Wizards of the Coast
- 15 April 2013An ability that triggers when something “attacks and isn’t blocked” triggers in the declare blockers step after blockers are declared if (1) that creature is attacking and (2) no creatures are declared to block it. It will trigger even if that creature was put onto the battlefield attacking rather than having been declared as an attacker in the declare attackers step.