Miasmic Rush

Miasmic Rush, along with PvP Worlds and the accompanying Zuriel's staff required to cast them, were released by Jagex on 15 October, 2008.

Miasmic Rush requires a Magic level of 61 and can do a maximum of 180 life points per spell, making it the strongest rush spell. In addition, any players affected by the spell will attack with melee or ranged 50% slower (weapon attack speed cut in half) for 12 seconds. As with all Ancient Magicks spells, the quest Desert Treasure must be completed to cast this spell. This is the weakest of the Miasmic spells and like all of them require Zuriel's staff, a rare weapon only obtainable from PvP drops to cast it, making it one of the first Ancient Magicks spells to require more than just runes to cast.

It is interesting to note, though, that to use it at level 61 you must use the corrupt version of the staff, as the regular version requires 78 magic to wield