Spell Lock
From WoWWiki
Felhunter skill, best described as a hybrid of Silence and Counterspell. When it is initially used, it will silence the target, regardless of the target's action. However, if the enemy was in the process of casting a spell, then the spell will be interrupted, and the target will be unable to cast a spell from the same school of magic for either 5 or 6 seconds. For example; if a Felhunter casts Spell Lock on a Mage, in the process of casting Frostbolt, the the spell will be cancelled, and the mage will be locked out of their other Frost spells for the duration of the debuff (either 5 or 6 seconds).
This is an instant-cast ability with a 24-second cooldown.
Spell Lock, like all of the Minion skills, can be set to Auto-cast, however, it might be more viable to disable this, as the AI will normally use the silencing part of the skill, as opposed to the interrupting part. Disabling auto-cast will allow the Warlock to decide if a spell is worth interrupting, or if the target is enough of a threat to use an interrupt on.
Misconceptions
As was previously believed, Spell Lock is not a pure interrupt skill. As below, in Patch 1.7, the silencing debuff was added, making this skill a dual purpose. It can be used to accurately interrupt a skill, or it can be used pre-emptively, to disable a caster for a short period of time, which will normally force the mob to enter melee range, where they are considerably weaker.
Changelog
- Patch 2.1 - "...duration reduced to 5 seconds (rank 1) and 6 seconds (rank 2), and cooldown reduced to 24 seconds."
- Previously, it was a 6/8 second duration, with a 30 second cooldown.
- Patch 1.7 - A 3-second silence debuff was added.

