Residual Rebound

Prerequisite(s): Exposure to spell resistance or spell turning spell.
Benefit: If you roll a natural 20 on a save against a targeted spell, it turns back on the caster as if affected by a spell turning spell. Unlike spell turning, however, the Residual Rebound feat potentially functions against touch range spells as well. Residual Rebound only works on targeted spells that allow a saving throw, so a fireball won't rebound, nor will a power word stun.
Source: Unearthed Arcana