Blind

Blind (a.k.a. Disorient) is a type of Crowd Control effect in Diablo II and Diablo III. Monsters very rarely use it (probably the only known example is Lysa), but player skills often have it as a side-effect, and some items give a chance on hit to Blind target.

Diablo II
In Diablo II, Blind merely reduces accuracy of the enemy attacks, bringing their chance to hit to 5%. Other abilities, however, are unaffected.

Cloak of Shadows, Dim Vision and Ravens apply an effect that reduces the victim's vision radius and prevents them from using ranged attacks and most spells (but does not impair their melee combat capabilities).

Diablo III
While a Blind effect lasts, affected targets cannot move (technically, they wander around aimlessly in a very short-ranged circle, but do not count as Immobilized), are unable to attack and use active abilities, but the ongoing effects are not dispersed, and passive abilities are not suppressed. Channeled attacks of the monsters are also interrupted, so Blinding a monster while they prepare any charged-up attack will nullify that.

Blind is fully effective against all enemies, even against Bosses. It is potent enough to interrupt the bosses' attacks, up to an including the Red Lightning Hose. However, some Boss special attacks cannot be interrupted (like Belial's Meteor Strike in Phase 3, Malthael's Soul Sweep or Adria's Blood Rain). While these bosses, technically, are not immune to Blind, some of their special attacks are scripted events rather than actual abilities, and therefore do not depend on player's actions.

Crowd Control resistance reduces the duration of subsequent Blind effects.