[Snake]

Could be global if I might say. It only affects a single target anyway, the duration is not overbearingly long like a Hexer's curse skill, and it is an invocation. Since Priests don't benefit from High Speed Divine Words, it makes them harder to use their invocations without getting silenced mid-way by a cheeky Kensei/VA/Hexer/MG/Ghost/Boxer/Grand Summoner/Bonder/Lantern Bearer, so.

Give it some thought, global would be just right.