Capture Daylight

On spells that deal radiant or fire damage, player may roll 1d8 and reduce it by that much.  If cast at higher level, player may add an additional 1d8 per level. Players utters a capture phrase and while holding a glass bottle.  The damage is then stored in that glass bottle.  Player can then store bottle, which can be thrown in an attack later.  When captured spell bottle is thrown, target must make a Dex saving throw. A fail, the target takes the full damage value. On a success, target takes half.