You can modify a trap to become more tenacious.
Benefit: Whenever a creature targeted by a persistent trap or within its area succeeds on its saving throw against the trap, it must make another saving throw against the effect. If a creature fails this second saving throw, it suffers the full effects of the trap, as if it had failed its first saving throw. A persistent trap uses up a trap slot two levels higher than the trap’s actual level.
Traps that do not require a saving throw to resist or lessen the trap’s effect do not benefit from this feat.
Path of Iron, © 2015, Ascension Games, LLC; Author Christopher Moore