Element of Surprise is a tier 4 skill in Claptrap's Fragmented Fragtrap skill tree.

You randomly pick a Subroutine focused on one elemental type, increasing all damage of that element by +32% but decreasing damage of other elements by -16%. When your shield is depleted, filled or when you enter Fight For Your Life, you release a Nova of the chosen element.

Claptrap Skills
Boomtrap I Love You Guys! Fragmented Fragtrap