You’re a spellcaster’s worst nightmare.
If a non-mythic creature within 30 feet of you uses a spell or spell-like ability, you can expend one use of mythic power to make a ranged attack against that creature as an attack of opportunity (even if the creature wouldn’t normally provoke attacks of opportunity). You must have a ranged weapon in hand or have a free hand and the non-mythic Quick Draw feat to use this ability. You can use this ability against a mythic creature by expending two uses of mythic power.
Pathfinder Roleplaying Game Mythic Adventures © 2013, Paizo Publishing, LLC; Authors: Jason Bulmahn, Stephen Radney-MacFarland, Sean K Reynolds, Dennis Baker, Jesse Benner, Ben Bruck, Jim Groves, Tim Hitchcock, Tracy Hurley, Jonathan Keith, Jason Nelson, Tom Phillips, Ryan Macklin, F. Wesley Schneider, Amber Scott, Tork Shaw, Russ Taylor, and Ray Vallese.