Fear

Fear is a keyword ability found primarily on black creatures. It is an evasion ability that allows a creature to only be blocked by black or artifact creatures.

Description
The ability has existed since Alpha, where it was printed on a card called, appropriately, Fear. The rules text of that card was originally the rules text for the fear ability. The ability was first keyworded in the Onslaught set. It showed up in a core set for the first time in Eighth Edition. All pre-Onslaught cards have been errataed to replace the older rules text with the fear keyword. The vigilance, lifelink, and fear keywords are the only keywords with a card of the exact name (Vigilance, Lifelink and Fear respectively). Flying and indestructible come close, with cards called Flight and Indestructibility, respectively.

With Magic 2010 Wizards of the Coast obsoleted Fear, in favor of the new keyword Intimidate. Intimidate differs in that nonartifact creatures can block the creature if they share a color with the blocked creature. Thus, Intimidate can interact with color-changing effects, and a nonblack deck can be built to use it against black creatures. Intimidate would in its turn be obsoleted by Menace.

Rulings

 * Cards that change color words do not change the Fear ability. The reminder text on the card can change, but it's just reminder text and does not actually define the ability.

Enchantments that grant just Fear
One creature Creatures of the chosen type All your creatures
 * Fear
 * Sleeper's Guile
 * Sleeper's Robe</c>
 * Cover of Darkness</c>
 * Intimidation</c>