Power Block

Clarification

 * The effect of disabling spells of the same attribute will still take place even if the target's spell did not get interrupted (such as if target is protected by Mantra of Resolve. The disabling will cause the target's spell to fail, bypassing the anti-interruption effect.

Acquisition
Signet of Capture:
 * Lyssa's Cursed (Perdition Rock)

Usage Notes

 * In PvP play, many characters are entirely focused around a single attribute. Disabling a Monk's Healing Prayers attribute for 13 seconds offers more than enough time for any competent team to finish the job.
 * In PvE play, most bosses in the game (and foes for that matter) are one single profession, which increases the odds that they mainly use skills from a single attribute, which again gives Power Block a time to shine. However, this skill is less useful in this type of play than in PvP because foes seldom live long enough or are powerful enough to deserve simply disabling their skills.
 * In all cases, try to use Arcane Conundrum or Dazed to make it much easier to interrupt.

Related Skills
Mesmer
 * Blackout
 * Psychic Distraction

Ranger
 * Distracting Shot

Warrior
 * Disrupting Chop